Advanced Materials

Recreating the complex spatial gradients and multi-material transitions of native tissues remains a fundamental challenge in 3D bioprinting. To address this, we introduce multi-modal photoFRESH, which integrates localized photochemistry into embedded printing by delivering light through a fiber-optic light-pipe. By tuning numerical aperture, print speed, and photoabsorber content, we achieve precise layer-by-layer control of crosslinking, stiffness, and bioorthogonal biomolecular tethering while preserving high print fidelity. Both photoactivatable support baths and extruded bioinks can be patterned, together with traditional FRESH printing. Utility of the platform is demonstrated by the fabrication of structurally complex tissue scaffolds and cellularized muscle constructs with distinct mechanical and biochemical domains. This multi-modal approach expands the boundaries of embedded bioprinting toward functional and heterogeneous tissue architectures.

Implant-associated infections are driven by bacterial biofilm formation and remain difficult to eradicate using conventional antibiotic-based strategies. Here, we present a dynamically actuated reconfigurable topographical surface (DARTS) that integrates intrinsically bactericidal nanoscale surface topography with programmable mechanical actuation to achieve durable, antibiotic-free infection control. Using a scalable bottom-up nanofabrication strategy, we generate tunable wrinkled MXene topographies that exhibit contact-mediated bactericidal activity against both Gram-positive and Gram-negative bacteria without chemical leaching. Integration with a soft robotic actuator enables reversible modulation of surface geometry, which synergistically enhances bacterial removal and killing, resulting in near-complete disruption of mature biofilms. Dynamic actuation further sensitizes released bacteria to antibiotic treatment. In a mouse subcutaneous implant infection model, DARTS with actuation achieves sustained suppression of bacterial burden and markedly improves host tissue outcomes. Remote, noninvasive actuation using near-infrared laser stimulation further highlights the translational potential of this platform for implantable antibacterial applications.

Engineered epithelial models require three-dimensional extracellular matrix environments that support organized cell growth and allow independent access to luminal and basal compartments. However, many organ-on-chip (OoC) fabrication strategies rely on planar geometries, non-native materials, or multi-step assembly workflows that limit architectural complexity and experimental control. Here, we report a direct in-chip volumetric printing strategy for fabricating stretchable and perfusable collagen-I scaffolds inside custom OoC devices. A vitamin C-regulated ruthenium/sodium persulfate photocrosslinking system enabled high-fidelity printing of collagen-I into open-lumen architectures with ductal- and alveolar-inspired features. By generating scaffolds directly within the final culture device, this workflow eliminates post-print transfer and integrates defined collagen architectures with compartmentalized fluidic access and a mechanically actuable chip format. To support chip-based culture, printed collagen constructs were stabilized after fabrication using EDC/NHS chemistry, which limited thermally induced collagen densification, improved shape retention, and maintained scaffold anchorage during perfusion. The chip design provided separate access to the printed lumen and surrounding basal compartment, which enabled compartment-specific fluid handling while preserving scaffold integrity during inflation, stretching, and perfusion of the printed construct. On the collagen-I scaffolds, human milk-derived mammary epithelial cells formed epithelial layers with tight junctions and lactation associated markers. The platform further supported perfusion culture, in situ staining, and whole-chip volumetric imaging. Together, this work establishes direct in-chip collagen-I volumetric printing as a biofabrication strategy for creating perfusable epithelial tissue chips with native matrix architecture and compartmentalized fluidic control.

Miniaturized implantable bioelectronics offer breakthrough potential in disease treatment, biomarker monitoring, and physiological sensing. However, wireless power transfer (WPT) remains a central limitation for millimeter-scale devices, as scaling down the receiver size rapidly decreases coupling efficiency due to tissue attenuation, low quality-factors, reduced mutual inductance, and limited tolerance to spatial and angular displacement. Here, we introduce distributed resonant coupling (DRC), a 3-coil WPT paradigm which enables the receiver (Rx) to actively participate in a strongly coupled resonance, transforming the Rx from a passive energy harvester into an active participant in a strongly coupled regime. By co-designing transmitters (Tx), resonators (Rs), and mm-scale receiver coils (Rx) as fully coupled systems, DRC exhibits simulated maximum power levels of 66%, measured received power transfer efficiencies of [~]56%, and end-to-end DC power transfer efficiencies of 42%, delivering >420 mW to loads at 1 W of transmitted power while maintaining robust performance across a range of practically relevant orientations and tissue media. Systematic theoretical and experimental efforts establish core design rules for DRC systems enabling operation without specialized tuning integrated circuits or components. To illustrate the capabilities of DRC in practical applications in vivo, we demonstrate three technologies that capture a broad application space in bioelectronics: implant localization, rapid wireless battery charging, and ultraminiaturized drug delivery devices compatible with particulate drug formulations. Taken together, these results suggest operational capabilities across a wide range of angular tolerances (up to 60{degrees}), tissue depths and dielectric and scattering media.

Bioprinting increasingly requires biomaterials that are not only printable, but structurally adaptive and biologically instructive. Here we establish an ovoprotein-derived microgel platform that couples intrinsic protein bioactivity with orthogonal interparticle photocrosslinking for modular bioprinting. Methacrylated ovoproteins yielded a photoresponsive protein-rich hydrogel matrix with retained proteomic complexity, tunable mechanics, and cell-regulatory biofunction. Endogenous tyrosine chemistry drove interparticle dityrosine coupling between ovoprotein microgels, producing cohesive, microporous, and intrinsically autofluorescent granular networks. The resulting systems displayed programmable rheology and broad compatibility across digital light processing, extrusion-based and aspiration-assisted bioprinting. Functionally, the ovoprotein microgel matrices attenuated sustained pro-inflammatory macrophage activation, promoted endothelial organization and host angiogenic invasion, and supported spheroid-mediated vascular morphogenesis with progressive sprouting, lumenization, branching and inosculation. It further enabled bioprinted osteogenic constructs with long-term maturation into bone-like mineralized tissues in vitro. These findings establish ovoprotein microgel-spheroid bioassembly as an adaptive, bioinstructive strategy for engineering vascularized and mineralized tissue constructs.

Cell encapsulation offers a promising strategy for sustained therapeutic protein delivery, obviating the need for repeated injections. Among potential implantation sites, the subcutaneous space is particularly attractive for its accessibility and amenability to minimally invasive procedures. However, performance of subcutaneous devices reported to date has been limited due to various challenges including foreign body response (FBR) and inadequate mass transfer. Moreover, typical encapsulation devices require surgeries for implantation and retrieval, limiting their potential use in resource-limited settings. Here we present a miniaturized cell encapsulation platform comprising cells engineered to produce therapeutic proteins and an FBR-mitigating zwitterionic polyurethane nanofibrous membrane, in a thin cylindrical form factor compatible with applicator-based minimally invasive implantation and retrieval. Clonal mesenchymal stromal cells engineered to produce PGT121, a broadly neutralizing anti-HIV-1 antibody, were encapsulated and inserted subcutaneously, achieving long-term cell survival and sustained serum PGT121 concentrations for up to 36 weeks across multiple murine models. Cell-loaded devices retained therapeutic function after cryopreservation, supporting their potential use as an off-the-shelf product that can be centrally manufactured and implanted on-site without specialized infrastructure. The custom-designed applicator-based implantation and minimally invasive retrieval procedures were demonstrated in a more clinically relevant minipig model. These mini-"cellular factories" represent a translatable strategy for sustained delivery of biologic drugs in resource-limited settings. One Sentence SummaryAn insertable and retrievable mini cellular construct enables sustained protein delivery, supporting its potential use in resource-limited settings.

Synthetic biology has advanced microorganisms to be programmed as production hosts, but its application to bacteria that inherently assemble extracellular materials remains limited. Komagataeibacter spp., natively synthesizes cellulose at the bacterial cell surface, creating a material-forming interface that has not been used as a programmable recruitment platform. Here we establish cell-surface display in Komagataeibacter intermedius and show that this interface can recruit defined proteins, making functionalization part of cellulose formation. By engineering LppOmpA, we displayed a fluorescent protein and genetically encoded capture modules (SpyTag and SilkTag) to selectively capture catcher-fused protein cargos onto K. intermedius cell surface. Recruitment of silk-derived structural protein before cellulose production generated silk-associated fibrous structures within the pellicles, with retained cargo signal after washing. The resulting biocomposite showed reorganized fibre-network morphology, increased surface hydrophobicity, mesoscale ordering, and improved wet-state compressive strength. Wild-type cells exposed to same conditions did not reproduce these changes, demonstrating that material properties arise from surface-directed recruitment rather than protein exposure alone. This work demonstrates the material-forming bacterial surface as a programmable engineering interface for organizing extracellular proteins, providing a general strategy for engineering living materials.

Scaling neural interfaces to ever-higher channel counts has accelerated rapidly with advances in thin-film fabrication, lithography, and connectorization, enabling passive arrays to reach thousands of channels and chart credible pathways to much larger formats. Integrating active electronics directly at the sensing sites offers a complementary route to higher channel density by reducing the number of interconnects required to access large arrays. Here we introduce a monolithic flexible thin-film integrated circuit platform for active neural sensing, inspired by active-matrix display technology. The system integrates dual-gate amorphous indium gallium zinc oxide transistors on polyimide substrates to implement in-pixel transconductance amplification and row-column time-division multiplexing, improving scability for high-channel-count applications. Co-optimization of device architecture, contact engineering, and a hybrid ceramic-polymer thin-film encapsulation yields stable operation with projected lifetimes exceeding 38 years under accelerated aging. In acute and chronic in vivo rat studies, the platform exhibits negligible thermal burden, robust sensory-evoked recordings, and stable functionality over 30 days despite tissue encapsulation. These results establish display-inspired flexible thin-film electronics as a scalable building block for next-generation neural interfaces.

Controlled biomineralization is central to engineering physiologically relevant hard-tissue models, yet achieving spatially organized, three-dimensional (3D) mineral deposition in microfluidic on-chip systems remains challenging. While cell-based bone-on-chip platforms offer biological complexity, they intrinsically couple mineral initiation to confounding factors such as matrix remodeling and paracrine signaling, obscuring the earliest biochemical drivers of nucleation. Drawing inspiration from bottom-up synthetic biology, we engineered an enzymatically active granular matrix that recapitulates a key osteogenic function within a perfusable 3D microenvironment. Alkaline phosphatase (ALP), the key driver of native bone formation, was covalently conjugated to poly(ethylene glycol)-based (PEG) microgels via thiol-ene photochemistry, retaining over 90% enzymatic activity after 48 h. These monodisperse microgels were assembled into a jammed, perfusable matrix within an on-chip chamber, enabling independent control over enzyme loading and substrate delivery. The system supported rapid in situ mineralization (24-48 h), yielding a carbonated, calcium-deficient, apatite-like phase characteristic of early-stage bone mineral. We demonstrate that the spatial 3D localization of enzymatic activity to discrete microscale compartments, coupled with interstitial perfusion, enables localized and near-physiological mineral formation. This mechanistically defined, acellular platform provides a programmable foundation for investigating ALP-driven 3D mineralization and establishes a modular route toward hybrid biosynthetic models of (patho)physiological tissue mineralization.

With the push towards accessible benchtop models to capture biological events, many researchers are reaching for hydrogel platforms for 3D tissue engineering ex vivo. Recapitulating the dynamic mechanical environment cells experience in vivo requires dynamic hydrogel scaffolds whose mechanical properties can be reprogrammed with spatiotemporal precision. Here we describe a chemically simple hydrogel platform that undergoes visible-light photosoftening via a ruthenium-based photocleavable crosslinker, leveraging tetrazine-norbornene inverse electron demand Diels Alder (iEDDA) click chemistry between RuTetrazine crosslinker and norbornene-modified hyaluronic acid (NorHA). Nitrogen gas evolved during this reaction is repurposed as an intrinsic porogen, nucleating macropores (55-175 {micro}m) directly during gelation. Initial stiffness (1.5-10 kPa) and softening extent (from 50%-100% drop in storage modulus) are independently tunable through polymer and crosslinker composition. We have found RuTetrazine to be non-mutagenic and non-toxic (>80% live cell populations) once network-bound (IC50 = 0.27 mM). In a cell-instructive network co-crosslinked with an MMP-RGD-bearing peptide, human mesenchymal stromal cells (hMSCs) photosoftened in situ (2.27[-&gt;]0.54 kPa, [~]76%) spread approximately six-fold relative to stiff controls ([~]6,500 vs. [~]1,100 {micro}m2, p < 0.0001). This work demonstrates a synthetically accessible photocleavable crosslinker and a simple, macroporous hydrogel for modulating dynamic mechanical cues in three dimensions.

Tertiary lymphoid structures (TLSs) are organized three-dimensional immune niches associated with improved antitumor immunity, which has galvanized efforts to induce them artificially using biomaterials. However, these strategies have largely focused on soluble cue delivery, leaving the role of scaffold physical properties poorly understood. Here, we developed injectable, liposome-crosslinked supramolecular hydrogels spanning soft and stiff formulations to determine how scaffold mechanical properties regulate in situ tertiary lymphoid neogenesis. The formulations differed in their viscoelastic properties while maintaining broadly comparable release of ovalbumin and LIGHT. Soft hydrogels underwent distributed cellular infiltration and material replacement, transitioning from an early myeloid-rich response to vascularized, lymphoid-dominant tissues containing B-cell-rich aggregates adjacent to T-cell regions, with B-cell organization peaking at day 14. Single-cell RNA sequencing revealed that transient interferon-associated neutrophil and macrophage states in the early niche preceded the emergence of TLS-associated transcriptional programs across lymphoid and myeloid populations. In contrast, stiff hydrogels resisted infiltration and perpetuated a niche dominated by activated myeloid cells with limited lymphoid organization. Prophylactically implanted soft hydrogels improved early melanoma control relative to stiff hydrogels under checkpoint blockade, and a single soft-hydrogel implantation restrained tumor growth even without checkpoint blockade. Together, these findings establish scaffold mechanics and remodeling as active regulators of engineered immune-tissue organization and provide design principles for directing the development of local TLS-like niches.

Engineering biomimetic tissues with dynamically evolving 3D architectures represents an important direction for next-generation tissue engineering, as it enables recapitulation of the continuous morphogenesis of native tissues during development and regeneration. Here, a self-actuating 4D cell-strand bioprinting platform is developed to engineer complex tissue architectures through autonomous cell contractile force (CCF)-driven morphing without requiring external stimuli. The platform integrates a mechanically compliant and self-softening base hydrogel with embedded high-density cell strands printed using a fast-degrading carrier bioink. During culture, the carrier bioink rapidly degrades while the encapsulated cells proliferate and establish connected cellular networks, generating localized contraction that drives programmable shape transformation. Through spatial patterning of embedded cell strands, constructs with diverse morphologies, including V-shaped, helical, folded, and tubular architectures, are generated via controllable self-actuated morphogenesis. The platform further enables engineering of cartilage-like and bone-like tissues with well-defined curvature configurations and mechanically robust tissue matrices. In addition, programmable multi-tissue engineering is demonstrated through fabrication of a muscle-tendon junction-mimicking construct containing spatially organized fibroblast and myoblast compartments. This self-actuating 4D bioprinting strategy enables highly programmable and directionally controlled morphogenesis using a simple construct design with low cell amount requirements, providing a versatile platform for engineering dynamic tissue architectures.

Phenotypic biosensors that measure bacterial viability and antimicrobial susceptibility are essential for rapid infectious disease diagnostics, yet their speed is fundamentally limited by the rate at which bacteria encounter reporter molecules, a transport bottleneck that has been typically addressed by complex microfluidic solutions. Here we show that this bottleneck can be overcome by engineering transport directly into the sensing material. A multifunctional ionic hydrogel matrix, co-encapsulating bacterial growth medium and the redox reporter resazurin, exploits swelling-driven convective transport to dramatically accelerate bacteria-reporter interactions without any change to assay chemistry. By systematically tailoring the hydrogel crosslinking density and optimizing the encapsulated nutrient-osmotic microenvironment, we maximize metabolic signal generation to achieve a 12-to-48-fold reduction in detection time relative to solution-phase and conventional hydrogel assays. Deployed in a standard 96-well format for urinary tract infection (UTI) diagnosis of 48 clinical samples, the platform rapidly detects infection in 15 minutes to 2 hours, achieving 95% sensitivity and 100% specificity for bacterial detection, and 100% sensitivity and 98% specificity for antimicrobial susceptibility profiling, compared to time-consuming gold-standard urine culture-based methods. Results are readable both quantitatively on a plate reader and visually as a colorimetric assay, enabling point-of-care deployment without additional instrumentation. Thus, embedding transport enhancement within the sensing matrix, represents a general and scalable design principle for accelerating interaction-limited biosensing, which has excellent scope for rapid diagnostic development.

Light scattering in scintillators is a pervasive problem and a key factor limiting X-ray imaging resolution. Here, we shift scintillator radioluminescence from the traditional visible range into the short-wave infrared (SWIR) or near-infrared II (NIR-II, 1000-3000 nm) window to mitigate light scattering and thereby enhance light penetration and X-ray imaging resolution. We present an NIR II MgGa2O4:Ni2+ scintillator with peak emission at 1340 nm, achieving a threefold improvement in X-ray imaging resolution compared with visible scintillators owing to reduced light scattering. This heavy-metal-free NIR-II scintillator exhibits intense radioluminescence comparable to that of conventional visible-emitting CsI:Tl, achieving a detection limit of 56 nanograys per second, ~100-fold lower than typical doses used in medical imaging. We show that this NIR-II scintillator enables high-resolution X-ray radiography of electronic circuit boards and biological tissues.

Control over network dynamics at different length scales is a feature of natural materials challenging to replicate in synthetic hydrogels. Hydrogel viscoelasticity is commonly controlled by tuning the kinetics of reversible crosslinks; however, this strategy inherently links the resulting macroscale and nanoscale dynamics of the individual network components. Taking inspiration from biological materials that feature lipids as structural elements, we introduce Lipid Network Crosslinked (LINC) hydrogels that exploit the mobility of individual lipids within self-assembled liposomes as covalent, network-crosslinking points. These mobile, covalent crosslinks increase hydrogel stress relaxation rates over 20-fold compared to polymer-only hydrogels with equivalent crosslinking chemistries and stiffnesses. We demonstrate that liposome design parameters, including degree of surface functionalization and tail saturation, provide a means to independently control the macroscale storage moduli and stress relaxation behavior. Finally, as an application where control over network dynamics at different length scales is critical, we placed cell-adhesive ligands onto more mobile or less mobile network elements. Human neural progenitor cells cultured within LINC hydrogels of identical macroscale viscoelasticity significantly altered their phenotype in response to nanoscale ligand dynamics. These results establish LINC hydrogels as biomimetic materials that leverage nanoscale lipid mobility within a macroscale polymeric network to control dynamics at multiple length scales.

Precise drug delivery within anatomically complex tissues demands systems capable of both active navigation and deep tissue access, properties that have remained difficult to reconcile in existing nanocarriers and microrobots. Here we introduce Dynabots, a dynamic microrobotic assembly constructed from multifunctional nanoparticles covalently linked by thermally cleavable molecular connectors. This nanoparticle-rich architecture enables the integration of magnetic, imaging, and therapeutic components while preserving a high content of functional material. Collective assembly imparts enhanced magnetic responsiveness and maneuverability, enabling controlled navigation through tortuous biological environments. Upon exposure to mild thermal stimuli, the assemblies undergo programmed disassembly, releasing individual nanoparticles that can diffuse through tissue for localized therapeutic action. We establish the programmable transitions, biocompatibility, and therapeutic efficacy of this process across in vitro and in vivo models, including real-time fluoroscopic guidance within anatomically realistic phantoms and live rodent and porcine systems. By integrating magnetic control, reconfigurable architecture, and stimulus-triggered disassembly, Dynabots unite navigational precision with tissue permeability, providing a versatile platform for adaptive and deep-tissue drug delivery.

Governing thermal transport in engineered materials creates opportunities to redirect and recover the excess heat generated in electronic and energy-conversion devices. Materials that pair low cross-plane thermal conductivity with high in-plane thermal conductivity are particularly valuable because they confine heat and channel it away from sensitive regions, preventing localized device failure. Two-dimensional crystals are efficient building blocks for such anisotropic thermal conductors, but they are brittle, and the polymer composites used to toughen them usually forfeit much of the intrinsic anisotropy: in conventional percolation-based design, filler fraction is the only handle available, and it governs both in-plane and cross-plane conduction. Here we report a composite of Ti3C2Tx (MXene) nanosheets and squid ring teeth (SRT) inspired recombinant tandem-repeat (TR) proteins in which the protein serves as a molecular template and bridge, setting the spacing between nanosheets with angstrom-level precision through the number of tandem-repeat units and independently of the filler fraction. This structural handle provides a second, independent design parameter. At a fixed MXene loading, the number of repeats tunes the cross-plane conductivity (0.30 to 0.93 W/mK) and, with it, the thermal anisotropy ratio over a wide range (from about 70 down to 17), while the in-plane conductivity stays high (16 to 21 W/mK). We rationalize these trends with a Gaussian Network Model (GNM) of the protein embedded in a two-phase layered medium, which reproduces the measured directional conductivities from a single structural parameter and identifies the protein gallery as the cross-plane bottleneck. Extending the model to a mechanically loaded five-period stack, we find that the anisotropy is robust to reversible compression and twist, changing by only a few percent, so the number of tandem repeats, not the applied strain, is the dominant design handle. Because anisotropy is tuned structurally rather than volumetrically, these protein-MXene composites decouple thermal anisotropy from filler content, pointing toward flexible thermal materials that are not bound by the rules of mixture and percolation.

Gastrointestinal anastomotic leakage (AL) remains a life-threatening complication following gastrointestinal surgery, where outcomes critically depend on timely diagnosis. Current diagnostic strategies rely on periodic sampling and resource-intensive analysis in centralized laboratories. Here, we present a sterilizable, time-integrating hydrogel sensor platform for continuous, infrastructure-free monitoring of the patient's postoperative drain fluid. We introduce enzyme-responsive macromolecular networks for semi-quantitative bedside assessment of leak-associated digestive enzymes. The sensors retain functionality following lyophilization and ethylene oxide sterilization, enabling long-term storage and scalable deployment around the world. In a Swiss clinical cohort of 56 patients, including 19 with gastrointestinal anastomotic leakage, the sensor detected amylase-associated leaks two days (median) prior to clinical diagnosis with a sensitivity of 78% (95% CI 55-91) and a specificity of 95% (95% CI 82-99). The prospective validation in an independent cohort of 37 patients in Colombia, including seven patients with leaks, demonstrated 100% sensitivity (95% CI 64.6-100) and a 100% negative predictive value (95% CI 87.9-100.0), with sensor activation preceding standard clinical diagnosis by a median of five days. By converting episodic biochemical measurements into continuous, cumulative visual records, this infrastructure-free material platform enables close-meshed postoperative monitoring and may facilitate earlier recognition of anastomotic leakage across diverse healthcare settings.

While natural infections expose the immune system for days to weeks of inflammation and antigen presentation, immunizations with conventional bolus vaccines often lead to rapid clearance of antigens and adjuvants. Prolonged exposure to vaccines using controlled delivery devices or repeated dosing regimens has been shown to enhance germinal center reactions, leading to improved humoral responses, including increased magnitude of antibody titers and enhanced neutralizing activity. Herein, we report the use of injectable polymer-nanoparticle (PNP) hydrogels as a vaccine depot technology for sustained delivery of the clinically relevant SARS-CoV-2 Hexapro subunit antigen and a toll-like receptor agonist adjuvant. In mice, we demonstrated that PNP hydrogel vaccines enhanced germinal center responses and antibody responses relative to bolus vaccination. In nonhuman primates, hydrogel vaccines induced enhanced and durable antibody responses against wildtype and variants of concern such as Omicron BA.5 compared to bolus vaccination. We report the first use of a biomaterials-based approach for sustained delivery of vaccines in nonhuman primates, further advancing toward clinical translation.

The rise of antifungal resistance and limited antifungal drug classes creates an urgent need for biomaterials with localized, programmable activity. Here, we engineered curli nanofibers displaying the antifungal peptide heliomicin and unexpectedly discovered that wild-type CsgA itself exhibits intrinsic antifungal activity against Candida albicans, reducing fungal viability by approximately 2 log units. Heliomicin fusion enhanced this activity to a 3.5-log fungicidal reduction while preserving nanofiber self-assembly, hydrogel formation, mechanical properties, and 3D printability. Mechanistic analyses linked enhanced activity to membrane disruption and expansion of the cationic surface of CsgA. Heliomicin-CsgA hydrogels further reduced fungal burden and suppressed hyphal development in an ex vivo porcine skin infection model. These findings reveal that extracellular protein nanofibers can harbor intrinsic biological activities that can be uncovered and enhanced through protein engineering, establishing a strategy for developing intrinsically bioactive, programmable biomaterials for localized therapeutic applications against fungal pathogens and potentially other microbial infections.