Immune checkpoint blockade (ICB) therapies targeting the PD-1/PD-L1 axis have shown clinical promise, yet most patients do not achieve durable responses due to adaptive PD-L1 upregulation and recycling. While nanoparticle-based proteolysis targeting chimeras (PROTACs) offer a strategy for direct PD-L1 degradation, their therapeutic potential remains largely untapped because of a fundamental barrier: the inevitable formation of a nonspecific protein corona that severely limits target engagement. Here, we introduce a corona-free nano-PROTACs platform (CF-nPTs) that overcomes this obstacle. By integrating DSPE-PCB─a zwitterionic antifouling amphiphile with exceptional resistance to protein adsorption─into micellar nano-PROTACs, we construct a nano-PROTACs system capable of maintaining an ultraclean surface in biological fluids. Compared with previously reported Au, liposomal, and micellar based nano-PROTACs platforms, the CF-nPTs effectively resisted nonspecific protein adsorption, markedly enhanced the corecruitment of PD-L1 and E3 ligase, and enabled highly efficient proteasome-mediated PD-L1 degradation. Additionally, the corona-free architecture also promoted robust lymph-node targeting, further amplifying immunotherapeutic efficacy. As a result, CF-nPTs achieved pronounced tumor regression, extended survival, and strong immune activation in both subcutaneous melanoma and lymph-node-metastasis models. Collectively, this study identifies protein-corona resistance as a key determinant of nano-PROTACs performance and establishes CF-nPTs as a promising platform for efficient target protein degradation.

Longitudinal monitoring of neurochemical dysregulation during glioblastoma (GBM) progression is essential for elucidating tumor-neuron interactions and advancing neuroprotective strategies. Current methods, however, are limited by insufficient temporal resolution, spatial precision, and operational stability in the complex tumor microenvironment. We present a microelectrode sensing platform featuring carbon-coordinated transition metal nanocatalysts (CoCx@C) for in situ, high-fidelity tracking of dopamine (DA), a key modulator of neurological function. The engineered coordination structure facilitates rapid, selective multielectron DA oxidation, while its modulated d-band center minimizes nonspecific interfacial adsorption, yielding 278-fold sensitivity and 333-fold selectivity improvements over conventional electrodes. Longitudinal DA tracking across multiple models with this platform reveals novel insights into GBM-associated neural dysfunction. This work provides the first electrochemical evidence of neurotransmitter-mediated tumor-neuron interplay and offers a robust tool for cancer neuroscience investigations and beyond.

Nonspecific adsorption remains a persistent obstacle in biosensing applications, as it adversely impacts key performance indicators of biosensors such as sensitivity, specificity, and operational stability. Although conventional antifouling peptides have achieved much success, their practical utility is often constrained by susceptibility to enzymatic hydrolysis as natural enzymes exist in biological fluids. Herein, a robust nonfouling biosensor is proposed based on a newly designed peptide (δ-P) with both antifouling, antienzymatic degradation and recognition capabilities, functionalized with a δ-L-lysinyl-L-glutamic acid dimer. Crucially, the antifouling domain of the peptide is composed of a δ-L-lysinyl-L-glutamic acid dimer (glutamic acid with the lysine side chain), and the recognition domain specific for the protein ANXA1 is composed of D-type amino acids, and both of them are capable of resisting enzymatic degradation. Two types of proteases (alkaline protease and trypsin), which represent less site-specific and site-specific cleavage proteases, respectively, were tested to illustrate proteolysis. Taking advantages of the designed peptide, a highly sensitive and low-fouling electrochemical biosensor (with a linear range of 0.001-1000 ng mL-1 and a detection limit of 0.32 pg mL-1), capable of assaying protein ANXA1 in human sera, was prepared by attaching the peptide onto the electrode modified with a poly(3,4-ethylenedioxythiophene)-sodium alginate (PEDOT@SA) film and gold nanoparticles. More interestingly, the biosensor showed satisfactory accuracy for the detection of ANXA1 in undiluted clinical serum samples (verified by the ELISA method). It is anticipated that the peptide designing strategy presented in this work can be easily extended to the development of various robust antifouling biosensors capable of assaying targets in complex biological environments.

Electrochemically modulating the geometry of gold nanostructures for enhanced electrochemistry and antifouling performance.

Surface chemistry effects on electrochemical impedance spectroscopy of biomacromolecule interactions.

Electrode fouling is a daunting challenge during the electrochemical detection of uric acid (UA), particularly in complex biological environments. Herein, silanized reduced graphene oxide was explored as an antifouling platform to modify glassy carbon electrode (GCE) for the electrochemical detection of UA. Silanization imparts less polarity to the rGO surface upon introducing bulky siloxane groups that effectively minimizes non-specific adsorption of biomolecules. In order to evaluate the impact of different silane molecules on the antifouling performance, three different silanes, namely, triethoxymethylsilane (TEMS), dodecyltrimethoxysilane (DTMS), and trimethoxyphenylsilane (TMPS), were employed individually for rGO functionalization. Of these modified electrodes, rGO-TEMS/GCE and rGO-TMPS/GCE showed superior electrochemical responses toward UA, with rGO-TMPS/GCE exhibiting enhanced resistance to both electrochemical fouling and biofouling. rGO-TMPS/GCE maintained a stable current response after 1 h of incubation in a solution containing effective foulants such as bovine serum albumin (BSA) and cytochrome c (Cyt c). As a result, rGO-TMPS/GCE was further employed for the detection of UA by differential pulse voltammetry (DPV). The modified electrode exhibited a limit of detection of 0.76 μM ± 0.14 (N = 3), with a sensitivity of 1.04 μA μM-1 cm-2. These results emphasize the usefulness of rGO-TMPS/GCE as an effective antifouling electrode material for the stable and sensitive detection of UA.

Non-specific protein adsorption compromises the accuracy of biosensor measurements. Although hydrophilic and zwitterionic surface modifications have been proposed as solutions, their practical implementation is hindered by their chemical instability and complex synthesis routes. To address these limitations, we developed a simpler yet effective alternative: a fluorinated copolymer-based hydrophobic coating termed SHIELD. The copolymer was synthesized from 2,2,2-trifluoroethyl methacrylate, which imparts low surface energy and enhances hydrophobicity, and n-butyl acrylate, which confers mechanical flexibility and strong substrate adhesion. The copolymer was uniformly deposited onto diverse substrates through a single-step spin-coating process. The resulting surface exhibited strong antifouling performance in both protein adsorption and cell adhesion assays. Importantly, the coating thickness was precisely tunable by varying the polymer concentration, enabling optimization of antifouling efficacy. These findings demonstrate that the SHIELD coating can be stably and reproducibly applied across a wide range of substrates. Overall, this study presents a robust and facile surface modification strategy with strong potential for antifouling applications in biosensing platforms.

Solid-state nanochannels, as an emerging single-molecule sensing platform, have shown great potential in environmental monitoring, biomedical diagnostics, and food safety owing to their high stability, tunable geometry, and facile surface functionalization. However, in complex matrices, nonspecific adsorption, ion competition, and background noise often compromise the accuracy and reliability of detection. In recent years, interfacial modification has provided effective solutions to these challenges. This review summarizes various interfacial engineering methods for solid-state nanochannels, focusing on three main aspects: stability enhancement, specific recognition, and signal amplification. For stability enhancement, strategies such as antifouling coating, surface charge/hydrophilicity regulation, and covalent crosslinking are highlighted. For specific recognition, structure-adaptive modification, biomimetic engineering, and cooperative self-assembly are discussed. For signal amplification, in situ nucleic acid amplification, nanotag-assisted amplification, and catalysis-mediated signal amplification are presented. Finally, current challenges and future perspectives are outlined, emphasizing that the integration of interfacial modification with multidisciplinary approaches, including nanomaterials, molecular engineering, and artificial intelligence-driven signal processing, which will further advance high-precision detection in complex matrices.

This paper presents the optimization of surface modification for aptameric graphene nanosensors for the measurement of biomarkers in undiluted physiological media. In these sensors, graphene transduces the binding between an aptamer and the intended target biomarker into a measurable signal while being coated with a polyethylene glycol (PEG) nanolayer to minimize nonspecific adsorption of matrix molecules. We perform a systematic study of the aptamer and PEG attachment schemes and parameters, including the impact of the serial or parallel PEG–aptamer attachment scheme, PEG molecular weight and surface density, and aptamer surface density on the sensor behavior, such as the responsivity to biomarker concentration changes, and importantly, they are used for operation in physiological media and have the ability to reject nonspecific binding to interfering molecules. We then use the understanding from this parametric study to identify graphene nanosensor designs that are optimally functionalized with PEG and aptamers to be strongly responsive to target biomarkers and effectively reduce nonspecific adsorption of interferents, thereby enabling sensitive and specific biomarker measurements in undiluted physiological media. The experimental results show that nanosensors that were optimized via serial modification with 5000 Da PEG at 15 mM and a 94 nt DNA aptamer at 500 nM allowed specific measurement of C-reactive protein (CRP) in undiluted human serum with a limit of detection (LOD) down to 27 pM, representing an up to 1000-fold improvement compared to previously reported CRP measurements.

Nowadays, specific biomarkers and detection methods for the early, rapid and non-invasive diagnosis of Alzheimer's disease (AD) are scarce. MiR-34a and miR-206 are both upregulated in the cerebrospinal fluid and peripheral fluids of AD patients. In view of the similar biochemical information between interstitial fluid (ISF) and blood and high proportions of RNAs in ISF, this work developed an integrated optical patch that combined hydrogel microneedles (MNs) extraction with on-site fluorescence detection for the simultaneous sensing of miR-34a and miR-206. A zwitterionic compound trimethylamine nitrogen oxide amphiphile (TMAO) was introduced to the matrix of MNs by co-modification with hyaluronic acid (HA) and methacrylic acid (MAA) to endow the novel MNs with adjustable swelling ability, as well as resistance to non-specific adsorption property. Moreover, to avoid signal interferences, we innovatively performed spatial average cutting on the MNs. By embedding two toehold-mediated strand displacement (TMSD) probes within MNs matrix, a dual-emission MNs optical patch for the two miRNAs was thereby constructed. As a potential non-invasive and accurate diagnostic tool of AD, the capability of the proposed optical patch was further demonstrated by simultaneously and on-site differentiating expression levels of miR-34a and miR-206 in ISF between normal and AD model mice.

Human blood plasma is the matrix of choice for clinical diagnostic applications. However, matrix effects associated with its complex composition interfere with the accurate detection of biomarkers that are often present at extremely low concentrations. This study investigates such matrix effects, particularly the nonspecific adsorption of blood plasma to the sensor surface and the interaction of endogenous antibodies with the used receptors, and shows how they can be discriminated using a surface plasmon resonance biosensor. Moreover, we describe a strategy to tackle matrix effects by combining sequential blood plasma/buffer injections, single-surface referencing, and the addition of an antibody against endogenous immunoglobulins to blood plasma. Finally, we apply this strategy to the detection of the cancer biomarker carcinoembryonic antigen in undiluted blood plasma, achieving detection limits of 12ng/mL using direct detection, and 225pg/mL using a sandwich assay with functional gold nanoparticles.

Evaporation-driven digital ELISA with micro-droplet arrays for ultrafast detection of low-abundance proteins.

Accurate and sensitive detection of biomarkers in complex biofluids is critical for early disease diagnosis and clinical monitoring but remains challenging due to nonspecific interference from abundant proteins and reducing agents. Here, we present a novel self-powered, anti-interference photoelectrochemical (PEC) immunosensor that combines a ferroelectric hybrid photoanode with a platinum-doped peptide hydrogel (Pt-PH) biocathode. The photoanode was fabricated by in situ transformation of TiO2 nanorod arrays into ferroelectric BaTiO3 (BTO), followed by electrostatic self-assembly of sulfur-doped carbon nitride (SCN) quantum dots, forming an SCN/BTO/TiO2 ferroelectric hybrid. The spontaneous polarization of ferroelectric BTO induces an internal electric field, enhancing charge separation and visible-light-driven photocurrent generation. The biocathode employs nitrogen-doped graphene (NG) as a conductive scaffold, coated with a Pt-PH layer derived from the short-peptide Fmoc-FEFKF doped with Pt nanoparticles, providing a highly hydrated antifouling interface that effectively suppresses nonspecific protein adsorption. The split-type configuration further minimizes interference from reducing agents in real biofluids. Using neuron-specific enolase as a model biomarker, the PEC immunosensor achieves sensitive, selective, and stable detection directly in physiological samples without external bias. This work offers a promising strategy for developing next-generation self-powered PEC biosensors with reliable antifouling performance for clinical diagnostics.

Extracellular vesicles (EVs) hold great potential as disease biomarkers due to their ubiquity, high stability, and rich biomolecular cargo, but their clinical translation hinges on simple yet efficient isolation. Here, immunomicrosphere-assisted inertial flow microfluidics (IM-IFM) is presented for high-throughput, high-purity EV isolation from whole blood, enabling subsequent proteomic profiling. The IM-IFM first converts nanoscale EVs into microscale PSMSs@EVs complexes using antibody-conjugated polystyrene microspheres (PSMSs) and then directly isolates EVs from whole blood based on inertial focusing effects. Experimental results demonstrate that this method can isolate EVs from 2 mL of whole blood within 1 h while minimizing nonspecific adsorption. Mass spectrometry-based proteomics confirmed the EV-specific origin of isolated proteins while demonstrating a similar depth of coverage and a superior performance in removing high-abundance plasma proteins comparable to that of the conventional UC method. Clinically, proteomic analysis of IM-IFM-isolated EVs from gastric cancer (GC) patient blood identified multiple GC-associated protein biomarkers such as POSTN, demonstrating its utility for noninvasive cancer diagnostics. This strategy combines the specificity of immunocapture with the efficiency of inertial microfluidics, offering great potential for advancing EV-based liquid biopsy and precision medicine applications.

The ordered cytomembrane coating nanotechnologies have aroused increasing attention in various medical aspects, including drug screening. However, this ordered coating necessitates prior chemical or biological labeling of the cytomembrane, which threatens the preservation of the membrane protein bioactivity on nanoparticles and introduces nonspecific adsorption. This paper reports the facile development of a label-free osteoblast membrane reversely coated with magnetic hydrochar nanospheres (OMR@MHNs) via the self-assembly of concanavalin A (ConA)-bonded MHNs and OMs. The sucrose-derived MHNs were covalently functionalized with ConA via aqueous amidation with its residual amino groups. Without any additional modification on OMs, the ordered reverse OM coverage onto MHNs with full exposure of the inner surface was driven by the specific affinity interaction between the immobilized concanavalin and inherent extracellular saccharides of the osteoblast. This interaction also achieved improved OM capacity and biocomposite stability. Using bioactive OMR@MHNs as the extraction nanoplatform, four specific ingredients including two new potentially osteogenetic chemicals of diphylloside A and sagittatoside C targeting the inner surface of OMs were smoothly identified from Epimedium brevicornu Maxim, which were hardly discovered via normal OM disorderly bonded MHNs. As verified by cell, molecular docking, cellular thermal shift assay, Western blot, and zebrafish tests, diphylloside A and sagittatoside C showed significant antiosteoporotic actions with binding membrane proteins of EPH receptor B4 and fibroblast growth factor receptor 1. This research facilitated the facile label-free construction of ordered bioadsorbent and high-activity screening of natural drugs.

The modification of tantalum oxide (Ta2O5) nanoparticles (NPs) with biocompatible polymers is crucial for their biomedical use. Such modification can prolong NP circulation in the bloodstream by minimizing salt-induced aggregation and reducing nonspecific protein adsorption onto their surface. Understanding the features of polymer–NP interactions is a key issue in the fabrication of nanostructures with required characteristics. The present work aims to provide a comprehensive comparative study of bovine serum albumin (BSA) adsorption on bare and polydopamine (PDA)-coated Ta2O5 NPs. The synthesized NPs were characterized via transmission electron microscopy, Fourier transform infrared spectroscopy, dynamic light scattering, and zeta potential measurements. Fluorescence and circular dichroism spectroscopy were also employed for the first-time investigation of the interactions of Ta2O5 NPs and Ta2O5@PDA NPs with BSA. The results obtained show that PDA coating significantly enhances the protein-binding affinity. Time-resolved measurements revealed signatures of Förster resonance energy transfer, confirming complex formation between NPs and BSA. Moreover, colloidal stability tests in phosphate-buffered saline indicated that the presence of adsorbed BSA improves the dispersion stability of bare and PDA-coated Ta2O5 NPs. These findings advance the understanding of protein–NP interactions and highlight the potential of PDA coatings for designing stable and functional nanostructures for biomedical applications.

Biofouling arises from non-specific adsorption of several components present in complex biofluids, such as full blood, on the surface of electrochemical biosensors, with a resulting loss of functionality. Most biomarkers of clinical relevance are present in biological fluids at extremely low concentrations, making antibiofouling strategies necessary in electrochemical biosensing. Here, we demonstrate the effect of a highly porous gold (h-PG) film electrodeposited on a gold screen-printed electrode (AuSPE) using a self-templated method via hydrogen bubbling as an antibiofouling strategy in electrochemical biosensor development following exposure of the electrode to bovine serum albumin (BSA) at two different concentrations (2 and 32 mg/mL). The h-PG film has a high electrochemically active surface area, 88 times higher than the AuSPE electrode, with a pore size ranging from 2 to 50 μm. A rapid decrease in the Faradaic current was observed with the unmodified AuSPE, attesting to the strong biofouling effect of BSA at both concentrations tested. Notably, the h-PG-modified electrode showed an initial peak current decline, more evident at a higher BSA concentration, followed by rapid electrode regeneration when the electrode was left idle in the biofouling solution. Similar results were obtained for unmodified and modified electrodes in real serum and plasma samples. The regeneration process, explained in terms of balance between h-PG pore size and protein size, the nanoscale architecture of the h-PG electrodes, and repulsive electrostatic forces, indicates the huge potential of the h-PG film for use in biomedical electrochemical sensing.

Pre-programming the protein corona: From avoidance to endogenous targeting.

Selective protein adsorption on biomaterial surfaces is pivotal for regulating cell behavior and tissue organization in regenerative medicine. However, conventional 2D culture platforms fail to replicate the aligned architecture characteristic of vascular tissues. This study investigates whether a poly (vinyl alcohol)-stearate (PVA-stearate) surface coating can differentially modulate protein adsorption to direct extracellular matrix (ECM) assembly and cell alignment. The PVA-stearate conjugate was synthesized via esterification and extensively characterized by XRD, DSC, TGA, FTIR, AFM, and XPS, confirming successful chemical integration and a uniform nanoscale topography with moderate roughness compared to uncoated controls. Protein interaction analyses (MALDI-TOF and BCA assays) revealed selective suppression of non-specific globular protein adsorption (albumin, insulin) while facilitating collagen fibrillar assembly. Fibroblast (L929) cultures on the modified surfaces exhibited delayed initial adhesion followed by progressive elongation, unidirectional alignment, and coordinated cytoskeletal organization within 48 h, whereas unmodified substrates supported random orientation and disordered ECM deposition. These findings demonstrate that the PVA-stearate coating functions as a bioinstructive interface, enabling protein-specific modulation and guiding biomimetic cell-ECM interactions. This scalable and fully synthetic approach offers promising applications in vascular tissue engineering, antifibrotic surface design, and regenerative medicine platforms requiring controlled cellular organization.

Integrated mass-charge transfer enhancement in PEMFCs via nonspecific Pt-sulfonate adsorption and surface-channel co-design