Multimodal probing of T-cell recognition with hexapod heterostructures.

Studies using antigen-presenting systems at the single-cell and ensemble levels can provide complementary insights into T-cell signaling and activation. Although crucial for advancing basic immunology and immunotherapy, there is a notable absence of synthetic material toolkits that examine T cells at both levels, and especially those capable of single-molecule-level manipulation. Here we devise a biomimetic antigen-presenting system (bAPS) for single-cell stimulation and ensemble modulation of T-cell recognition. Our bAPS uses hexapod heterostructures composed of a submicrometer cubic hematite core (α-Fe2O3) and nanostructured silica branches with diverse surface modifications. At single-molecule resolution, we show T-cell activation by a single agonist peptide-loaded major histocompatibility complex; distinct T-cell receptor (TCR) responses to structurally similar peptides that differ by only one amino acid; and the superior antigen recognition sensitivity of TCRs compared with that of chimeric antigen receptors (CARs). We also demonstrate how the magnetic field-induced rotation of hexapods amplifies the immune responses in suspended T and CAR-T cells. In addition, we establish our bAPS as a precise and scalable method for identifying stimulatory antigen-specific TCRs at the single-cell level. Thus, our multimodal bAPS represents a unique biointerface tool for investigating T-cell recognition, signaling and function.

Monolithic silicon for high spatiotemporal translational photostimulation.

Electrode-based electrical stimulation underpins several clinical bioelectronic devices, including deep-brain stimulators1,2 and cardiac pacemakers3. However, leadless multisite stimulation is constrained by the technical difficulties and spatial-access limitations of electrode arrays. Optogenetics offers optically controlled random access with high spatiotemporal capabilities, but clinical translation poses challenges4-6. Here we show tunable spatiotemporal photostimulation of cardiac systems using a non-genetic platform based on semiconductor-enabled biomodulation interfaces. Through spatiotemporal profiling of photoelectrochemical currents, we assess the magnitude, precision, accuracy and resolution of photostimulation in four leadless silicon-based monolithic photoelectrochemical devices. We demonstrate the optoelectronic capabilities of the devices through optical overdrive pacing of cultured cardiomyocytes (CMs) targeting several regions and spatial extents, isolated rat hearts in a Langendorff apparatus, in vivo rat hearts in an ischaemia model and an in vivo mouse heart model with transthoracic optical pacing. We also perform the first, to our knowledge, optical override pacing and multisite pacing of a pig heart in vivo. Our systems are readily adaptable for minimally invasive clinical procedures using our custom endoscopic delivery device, with which we demonstrate closed-thoracic operations and endoscopic optical stimulation. Our results indicate the clinical potential of the leadless, lightweight and multisite photostimulation platform as a pacemaker in cardiac resynchronization therapy (CRT), in which lead-placement complications are common.

Periplasmic biomineralization for semi-artificial photosynthesis.

Semiconductor-based biointerfaces are typically established either on the surface of the plasma membrane or within the cytoplasm. In Gram-negative bacteria, the periplasmic space, characterized by its confinement and the presence of numerous enzymes and peptidoglycans, offers additional opportunities for biomineralization, allowing for nongenetic modulation interfaces. We demonstrate semiconductor nanocluster precipitation containing single- and multiple-metal elements within the periplasm, as observed through various electron- and x-ray-based imaging techniques. The periplasmic semiconductors are metastable and display defect-dominant fluorescent properties. Unexpectedly, the defect-rich (i.e., the low-grade) semiconductor nanoclusters produced in situ can still increase adenosine triphosphate levels and malate production when coupled with photosensitization. We expand the sustainability levels of the biohybrid system to include reducing heavy metals at the primary level, building living bioreactors at the secondary level, and creating semi-artificial photosynthesis at the tertiary level. The biomineralization-enabled periplasmic biohybrids have the potential to serve as defect-tolerant platforms for diverse sustainable applications.

A soil-inspired dynamically responsive chemical system for microbial modulation.

Interactions between the microbiota and their colonized environments mediate critical pathways from biogeochemical cycles to homeostasis in human health. Here we report a soil-inspired chemical system that consists of nanostructured minerals, starch granules and liquid metals. Fabricated via a bottom-up synthesis, the soil-inspired chemical system can enable chemical redistribution and modulation of microbial communities. We characterize the composite, confirming its structural similarity to the soil, with three-dimensional X-ray fluorescence and ptychographic tomography and electron microscopy imaging. We also demonstrate that post-synthetic modifications formed by laser irradiation led to chemical heterogeneities from the atomic to the macroscopic level. The soil-inspired material possesses chemical, optical and mechanical responsiveness to yield write-erase functions in electrical performance. The composite can also enhance microbial culture/biofilm growth and biofuel production in vitro. Finally, we show that the soil-inspired system enriches gut bacteria diversity, rectifies tetracycline-induced gut microbiome dysbiosis and ameliorates dextran sulfate sodium-induced rodent colitis symptoms within in vivo rodent models.

Porosity-based heterojunctions enable leadless optoelectronic modulation of tissues.

Homo- and heterojunctions play essential roles in semiconductor-based devices such as field-effect transistors, solar cells, photodetectors and light-emitting diodes. Semiconductor junctions have been recently used to optically trigger biological modulation via photovoltaic or photoelectrochemical mechanisms. The creation of heterojunctions typically involves materials with different doping or composition, which leads to high cost, complex fabrications and potential side effects at biointerfaces. Here we show that a porosity-based heterojunction, a largely overlooked system in materials science, can yield an efficient photoelectrochemical response from the semiconductor surface. Using self-limiting stain etching, we create a nanoporous/non-porous, soft-hard heterojunction in p-type silicon within seconds under ambient conditions. Upon surface oxidation, the heterojunction yields a strong photoelectrochemical response in saline. Without any interconnects or metal modifications, the heterojunction enables efficient non-genetic optoelectronic stimulation of isolated rat hearts ex vivo and sciatic nerves in vivo with optical power comparable to optogenetics, and with near-infrared capabilities.

A pulsatile release platform based on photo-induced imine-crosslinking hydrogel promotes scarless wound healing.

Effective healing of skin wounds is essential for our survival. Although skin has strong regenerative potential, dysfunctional and disfiguring scars can result from aberrant wound repair. Skin scarring involves excessive deposition and misalignment of ECM (extracellular matrix), increased cellularity, and chronic inflammation. Transforming growth factor-ß (TGFß) signaling exerts pleiotropic effects on wound healing by regulating cell proliferation, migration, ECM production, and the immune response. Although blocking TGFß signaling can reduce tissue fibrosis and scarring, systemic inhibition of TGFß can lead to significant side effects and inhibit wound re-epithelization. In this study, we develop a wound dressing material based on an integrated photo-crosslinking strategy and a microcapsule platform with pulsatile release of TGF-ß inhibitor to achieve spatiotemporal specificity for skin wounds. The material enhances skin wound closure while effectively suppressing scar formation in murine skin wounds and large animal preclinical models. Our study presents a strategy for scarless wound repair.

Reducing alcohol and/or cocaine-induced reward and toxicity via an epidermal stem cell-based gene delivery platform.

Alcohol use disorder (AUD) is one of the foremost public health problems. Alcohol is also frequently co-abused with cocaine. There is a huge unmet need for the treatment of AUD and/or cocaine co-abuse. We recently demonstrated that skin grafts generated from mouse epidermal stem cells that had been engineered by CRISPR-mediated genome editing could be transplanted onto mice as a gene delivery platform. Here, we show that expression of the glucagon-like peptide-1 (GLP1) gene delivered by epidermal stem cells attenuated development and reinstatement of alcohol-induced drug-taking and seeking as well as voluntary oral alcohol consumption. GLP1 derived from the skin grafts decreased alcohol-induced increase in dopamine levels in the nucleus accumbens. In exploring the potential of this platform in reducing concurrent use of drugs, we developed a novel co-grafting procedure for both modified human butyrylcholinesterase (hBChE)- and GLP1-expressing cells. Epidermal stem cell-derived hBChE and GLP1 reduced acquisition of drug-taking and toxicity induced by alcohol and cocaine co-administration. These results imply that cutaneous gene delivery through skin transplants may add a new option to treat drug abuse and co-abuse.

Micelle-enabled self-assembly of porous and monolithic carbon membranes for bioelectronic interfaces.

Real-world bioelectronics applications, including drug delivery systems, biosensing and electrical modulation of tissues and organs, largely require biointerfaces at the macroscopic level. However, traditional macroscale bioelectronic electrodes usually exhibit invasive or power-inefficient architectures, inability to form uniform and subcellular interfaces, or faradaic reactions at electrode surfaces. Here, we develop a micelle-enabled self-assembly approach for a binder-free and carbon-based monolithic device, aimed at large-scale bioelectronic interfaces. The device incorporates a multi-scale porous material architecture, an interdigitated microelectrode layout and a supercapacitor-like performance. In cell training processes, we use the device to modulate the contraction rate of primary cardiomyocytes at the subcellular level to target frequency in vitro. We also achieve capacitive control of the electrophysiology in isolated hearts, retinal tissues and sciatic nerves, as well as bioelectronic cardiac sensing. Our results support the exploration of device platforms already used in energy research to identify new opportunities in bioelectronics.

HCF-1 promotes cell cycle progression by regulating the expression of CDC42.

The eukaryotic cell cycle involves a highly orchestrated series of events in which the cellular genome is replicated during a synthesis (S) phase and each of the two resulting copies are segregated properly during mitosis (M). Host cell factor-1 (HCF-1) is a transcriptional co-regulator that is essential for and has been implicated in basic cellular processes, such as transcriptional regulation and cell cycle progression. Although a series of HCF-1 transcriptional targets have been identified, few functional clues have been provided, especially for chromosome segregation. Our results showed that HCF-1 activated CDC42 expression by binding to the -881 to -575 region upstream of the CDC42 transcription start site, and the regulation of CDC42 expression by HCF-1 was correlated with cell cycle progression. The overexpression of a spontaneously cycling and constitutively active CDC42 mutant (CDC42F28L) rescued G1 phase delay and multinucleate defects in mitosis upon the loss of HCF-1. Therefore, these results establish that HCF-1 ensures proper cell cycle progression by regulating the expression of CDC42, which indicates a possible mechanism of cell cycle coordination and the regulation mode of typical Rho GTPases.

Laser writing of nitrogen-doped silicon carbide for biological modulation.

Conducting or semiconducting materials embedded in insulating polymeric substrates can be useful in biointerface applications; however, attainment of this composite configuration by direct chemical processes is challenging. Laser-assisted synthesis has evolved as a fast and inexpensive technique to prepare various materials, but its utility in the construction of biophysical tools or biomedical devices is less explored. Here, we use laser writing to convert portions of polydimethylsiloxane (PDMS) into nitrogen-doped cubic silicon carbide (3C-SiC). The dense 3C-SiC surface layer is connected to the PDMS matrix via a spongy graphite layer, facilitating electrochemical and photoelectrochemical activity. We demonstrate the fabrication of arbitrary two-dimensional (2D) SiC-based patterns in PDMS and freestanding 3D constructs. To establish the functionality of the laser-produced composite, we apply it as flexible electrodes for pacing isolated hearts and as photoelectrodes for local peroxide delivery to smooth muscle sheets.

[Effect of diabetic induced thioredoxin interacting protein (TXNIP) on islet cell senescence].

Objective: To investigate whether the increased expression of thioredoxin interacting protein (TXNIP) in diabetes affects the senescence of islet ß cells. Methods: Six normal mice (db/m) and six diabetic mice (db/db) were randomly selected. Fasting blood glucose was measured by blood sugar meter, the expression levels of TXNIP protein, p16, p21 and Rb in pancreatic tissues were detected by Western blot, senescence-associated beta-galactosidase activity in pancreatic tissue was determined by immunochemical staining. INS-1 islet beta cells were randomly divided into 7 groups (n=6), and transfected with lentiviruses (30 µl) for 4 to 6 hours, then was screened with puromycin (PM, 3 µg/m) for 7 days to construct normal group, scramble ShRNA group (interference with airborne poison group), TXNIP-ShRNA-1 group (TXNIP silence group-1), TXNIP-ShRNA-2 group (TXNIP silence group 2), TXNIP-ShRNA-3 group (TXNIP silence group 3), Ad-GFP group (overexpression of the air virus group), Ad-TXNIP-GFP group (TXNIP overexpression group) stably transferred INS-1 islet beta cell line. TXNIP protein expression was detected by Western blot, aging-related beta-galactosidase activity was detected by immunochemical staining, the changes of expression of p16, p21 and Rb was determined by Western blot. Results: Compared with normal mice, the fasting blood glucose of db/db group was increased significantly (P＜0. 01), the expression of TXNIP protein was increased significantly in pancreatic tissues(P＜0. 05), positive staining rate of ß- galactosidase was increased significantly in pancreatic tissues, p16/p21/Rb protein expression levels were increased significantly (P＜0. 05). Compared with Ad-GFP group, the positive staining rate of ß- galactosidase in Ad-TXNIP-GFP group was increased significantly, p16/p21/Rb protein expression levels were increased significantly (P＜0. 01). Compared to the scramble ShRNA group, the positive staining rate of ß- galactosidase in TXNIP-ShRNA group was decreased, p16/p21/Rb protein expression levels were decreased significantly (P＜0. 05). Conclusion: Diabetes can induce islet ß-cell senescence by up-regulating TXNIP expression.

Ultra-conformal drawn-on-skin electronics for multifunctional motion artifact-free sensing and point-of-care treatment.

An accurate extraction of physiological and physical signals from human skin is crucial for health monitoring, disease prevention, and treatment. Recent advances in wearable bioelectronics directly embedded to the epidermal surface are a promising solution for future epidermal sensing. However, the existing wearable bioelectronics are susceptible to motion artifacts as they lack proper adhesion and conformal interfacing with the skin during motion. Here, we present ultra-conformal, customizable, and deformable drawn-on-skin electronics, which is robust to motion due to strong adhesion and ultra-conformality of the electronic inks drawn directly on skin. Electronic inks, including conductors, semiconductors, and dielectrics, are drawn on-demand in a freeform manner to develop devices, such as transistors, strain sensors, temperature sensors, heaters, skin hydration sensors, and electrophysiological sensors. Electrophysiological signal monitoring during motion shows drawn-on-skin electronics' immunity to motion artifacts. Additionally, electrical stimulation based on drawn-on-skin electronics demonstrates accelerated healing of skin wounds.

Regulation of epidermal differentiation through KDF1-mediated deubiquitination of IKKα.

Progenitor cells at the basal layer of skin epidermis play an essential role in maintaining tissue homeostasis and enhancing wound repair in skin. The proliferation, differentiation, and cell death of epidermal progenitor cells have to be delicately regulated, as deregulation of this process can lead to many skin diseases, including skin cancers. However, the underlying molecular mechanisms involved in skin homeostasis remain poorly defined. In this study, with quantitative proteomics approach, we identified an important interaction between KDF1 (keratinocyte differentiation factor 1) and IKKα (IκB kinase α) in differentiating skin keratinocytes. Ablation of either KDF1 or IKKα in mice leads to similar but striking abnormalities in skin development, particularly in skin epidermal differentiation. With biochemical and mouse genetics approach, we further demonstrate that the interaction of IKKα and KDF1 is essential for epidermal differentiation. To probe deeper into the mechanisms, we find that KDF1 associates with a deubiquitinating protease USP7 (ubiquitin-specific peptidase 7), and KDF1 can regulate skin differentiation through deubiquitination and stabilization of IKKα. Taken together, our study unravels an important molecular mechanism underlying epidermal differentiation and skin tissue homeostasis.

Soft-Hard Composites for Bioelectric Interfaces.

Bioelectric devices can probe fundamental biological dynamics and improve the lives of human beings. However, direct application of traditional rigid electronics onto soft tissues can cause signal transduction and biocompatibility issues. One common mitigation strategy is the use of soft-hard composites to form more biocompatible interfaces with target cells or tissues. Here, we identify several soft-hard composite designs in naturally occurring systems. We use these designs to categorize the existing bioelectric interfaces and to suggest future opportunities. We discuss the utility of soft-hard composites for a variety of interfaces, such as in vitro and in vivo electronic or optoelectronic sensing and genetic and non-genetic modulation. We end the review by proposing new soft-hard composites for future bioelectric studies.

Rapid Discovery and Characterization of Synthetic Neutralizing Antibodies against Anthrax Edema Toxin.

Anthrax, a lethal, weaponizable disease caused by Bacillus anthracis, acts through exotoxins that are primary mediators of systemic toxicity and also targets for neutralization by passive immunotherapy. The ease of engineering B. anthracis strains resistant to established therapy and the historic use of the microbe in bioterrorism present a compelling test case for platforms that permit the rapid and modular development of neutralizing agents. In vitro antigen-binding fragment (Fab) selection offers the advantages of speed, sequence level molecular control, and engineering flexibility compared to traditional monoclonal antibody pipelines. By screening an unbiased, chemically synthetic phage Fab library and characterizing hits in cell-based assays, we identified two high-affinity neutralizing Fabs, A4 and B7, against anthrax edema factor (EF), a key mediator of anthrax pathogenesis. Engineered homodimers of these Fabs exhibited potency comparable to that of the best reported neutralizing monoclonal antibody against EF at preventing EF-induced cyclic AMP production. Using internalization assays in COS cells, B7 was found to block steps prior to EF internalization. This work demonstrates the efficacy of synthetic alternatives to traditional antibody therapeutics against anthrax while also demonstrating a broadly generalizable, rapid, and modular screening pipeline for neutralizing antibody generation.

Angiotensin II type i receptor agonistic autoantibodies induces apoptosis of cardiomyocytes by downregulating miR21 in preeclampsia: a mechanism study.

Angiotensin II type I receptor agonistic autoantibodies (AT1-AA) in the plasma of preeclampsia patients can induce apoptosis of cardiomyocytes, and microRNA-21 (miR-21) can exert a protective effect on cardiomyocytes. But whether the pro-apoptotic effect of AT1-AA is associated with miR-21 is unclear. The objective of the present study was to explore whether AT1-AA induced cardiomyocyte apoptosis was related to its inhibitory of miR-21 expression. In vivo studies, the pregnant rats were divided into two groups: Sham group, Model group. The pathology, cell apoptosis, and relative protein expressions were evaluated by hematoxylin and eosin staining, and Western blot assay. The expression of microRNA was detected by gene microarray. In the cell experiment, the neonatal rat cardiomyocytes were divided into four groups: NC group, AT1-AA group, and miR-21 group and AT1-AA+miR-21 group. The cell apoptosis and relative proteins' expressions were measured by flow cytometry and Western blot assay. Results: Compared with the Sham group, miR-21 in the cardiac tissue of the model group was downregulated significantly; the expression of p-JNK, Bax and caspases-3 was increased, the expression of Bcl-2 was decreased, and the Bcl-2/Bax ratio became smaller. The expression of miR-21 in AT1-AA treated cardiomyocytes was only 52% of the control group, with an apoptosis rate of 32.6%. In addition, the expression of pPTEN, pAKT and pFOXO3a in the model group was significantly higher than that in the NC group. The cardiomyocyte apoptosis rate in miR-21 overexpression group was only 23.7%, which was higher than that in the NC group, but significantly lower than that in AT1-AA group. PTEN, AKT and FOXO3a phosporylation in miR-21 overexpression group was also lower than that in AT1-AA group. AT1-AA induced cardiomyocyte apoptosis by downregulating miR-21, and the PTEN/AKT/FOXO3a signal transduction pathway participated in this process. The result of the present study suggests that miR-21 may prove to be a new target for the diagnosis and treatment of preeclampsia and other cardiovascular diseases.

NLRP3 inflammasome mediates angiotensin II-induced islet ß cell apoptosis.

Elevation of angiotensin II (Ang II) in the serum of patients with diabetes is known to promote apoptosis of islet ß cells, but the underlying mechanism remains unclear. The aim of the present study was to explore the role of Nod-like receptor protein 3 (NLRP3) inflammasome in Ang II-induced apoptosis of pancreatic islet ß cells and investigate the possible underlying mechanism. The effect of Ang II on INS-1 cell (a rat insulinoma cell line) viability was detected by CCK-8 method. The cell apoptosis was detected by flow cytometry and western blot analysis. The effect of Ang II on the expressions of thioredoxin-interacting protein (TXNIP) and NLRP3 protein was detected by western blot analysis. The expression of TXNIP mRNA was detected by real-time polymerase chain reaction. The results showed that Ang II was able to reduce INS-1 cell viability and promote apoptosis and at the same time up-regulate the expressions of TXNIP and NLRP3 components. Ang II-induced apoptosis was inhibited after administration of the NLRP3 inhibitor MCC950, and TXNIP silencing could reduce the NLRP3 expression and apoptosis, while both effects of Ang II on TXNIP-NLRP3 and its apoptosis-inducing effect were inhibited by angiotensin II type I receptor (AT1R) blocker Telmisartan. Our results demonstrated that the TXNIP-NLRP3 inflammasome pathway mediated Ang II-induced INS-1 cell apoptosis and might hopefully become a novel target for the treatment of diabetes mellitus.

Genome-edited skin epidermal stem cells protect mice from cocaine-seeking behaviour and cocaine overdose.

Cocaine addiction is associated with compulsive drug-seeking, and exposure to the drug or to drug-associated cues leads to relapse, even after long periods of abstention. A variety of pharmacological targets and behavioral interventions have been explored to counteract cocaine addiction, but to date no market-approved medications for treating cocaine addiction or relapse exist, and effective interventions for acute emergencies resulting from cocaine overdose are lacking. We recently demonstrated that skin epidermal stem cells can be readily edited by using CRISPR (clustered regularly interspaced short palindromic repeats) and then transplanted back into the donor mice. Here, we show that the transplantation, into mice, of skin cells modified to express an enhanced form of butyrylcholinesterase, an enzyme that hydrolyzes cocaine, enables the long-term release of the enzyme and efficiently protects the mice from cocaine-seeking behavior and cocaine overdose. Cutaneous gene therapy through skin transplants that elicit drug elimination may offer a therapeutic option to address drug abuse.

Rational design of silicon structures for optically controlled multiscale biointerfaces.

Silicon-based materials have been widely used. However, remotely controlled and interconnect-free silicon configurations have been rarely explored, because of limited fundamental understanding of the complex physicochemical processes that occur at interfaces between silicon and biological materials. Here, we describe rational design principles, guided by biology, for establishing intracellular, intercellular and extracellular silicon-based interfaces, where the silicon and the biological targets have matched properties. We focused on light-induced processes at these interfaces, and developed a set of matrices to quantify and differentiate the capacitive, Faradaic and thermal outputs from about 30 different silicon materials in saline. We show that these interfaces are useful for the light-controlled non-genetic modulation of intracellular calcium dynamics, of cytoskeletal structures and transport, of cellular excitability, of neurotransmitter release from brain slices, and of brain activity in vivo.