The need for rapidly developed diagnostic tests has gained significant attention after the recent pandemic. Production of neutralizing antibodies for vaccine development or antibodies to be used in diagnostic tests usually require the usage of recombinant proteins representing the infectious agent. However, peptides that can mimic these recombinant proteins may be rapidly utilized, especially in emergencies such as the recent outbreak. Here, we report two peptides that mimic the receptor binding domain of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and investigate their binding behavior against the corresponding human immunoglobulin G and immunoglobulin M (IgG and IgM) antibodies in a clinical sample using a quartz crystal microbalance (QCM) sensor. These peptides were immobilized on a QCM sensor surface, and their binding behavior was studied against a clinical serum sample that was previously determined to be IgG and IgM-positive. It was determined that designed peptides bind to SARS-CoV-2 antibodies in a clinical sample. These peptides might be useful for the detection of SARS-CoV-2 antibodies using different methods such as enzyme-linked immunosorbent assay (ELISA) or lateral flow assays. A similar platform might prove to be useful for the detection and development of antibodies in other infections.

Antimicrobial peptides (AMPs) are a diverse group of small, naturally occurring molecules that orchestrate the innate immune response of various organisms, from microorganisms to humans. Characterized by their broad-spectrum activity against bacteria, fungi and viruses, AMPs are increasingly recognized for their potential as novel therapeutic agents in the face of rising antibiotic resistance. Here, we present several newly designed AMPs, one of which, DTN6, exerts significant activity against several organisms with MIC values as low as 0.5 µg/mL. The D-TN6 peptide influences both bacteria and yeasts. Scanning electron microscopy and transmission electron microscopy results showed that the bacterial membrane is affected by D-TN6, which is resistant to proteases and is effective against antibiotic-resistant pathogens with hemolytic activity and low toxicity. The D-TN6 peptide is effective in vivo against standard S. aureus strains in wounds. Thus, D-TN6 is a potent antibiotic candidate with a broad spectrum of activity. Overall, AMPs are a promising tool for the development of next-generation antimicrobial agents that could mitigate global health threats posed by multidrug-resistant pathogens.

Background: Hydrolyzed collagen peptides (HCP) are widely used as bioactive ingredients in anti-aging and skin rejuvenation formulations due to their role in supporting skin hydration, elasticity, and extracellular matrix integrity. However, their high hydrophilicity limits effective incorporation into lipid-based systems, and restricts controlled release from formulations. Objective: In this study, ethosomal nanocarriers were designed as a phospholipid–ethanol-based system to promote favorable molecular interactions with hydrophilic peptides, aiming to enhance the encapsulation, stability, and controlled release of HCP for dermocosmetic applications. Methods: HCP-loaded ethosomes were prepared using phospholipid (Lipoid P75) and ethanol and optimized by varying high-pressure homogenization cycles. Physicochemical properties, including vesicle size, distribution uniformity, zeta potential, pH, and long-term stability, were monitored for up to 180 days. Vesicle morphology and peptide–lipid interactions were characterized using cryo-scanning electron microscopy and FTIR spectroscopy. Encapsulation efficiency was determined by ultrafiltration, while cytocompatibility was assessed in HaCaT keratinocyte cells. In vitro release behavior was investigated using Franz diffusion cells and compared with aqueous HCP solutions. Results: All formulations exhibited nanoscale size distribution and high colloidal stability, with negative zeta potentials ranging from −42.9 to −76.7 mV. The optimized formulation demonstrated sustained encapsulation efficiency (73% after 180 days) and preservation of peptide structure, as confirmed by FTIR, indicating effective chemical stabilization within the ethosomal matrix. Cytotoxicity studies confirmed good skin cell compatibility. In vitro release studies revealed a controlled and prolonged release profile from ethosomal carriers compared with free HCP solutions, suggesting improved topical bioavailability of collagen peptides. Conclusions: To the best of our knowledge, this work provides one of the first systematic investigations of optimized ethosomal systems for the stabilization of hydrophilic collagen peptides as anti-aging dermocosmetic ingredients. These findings demonstrate that optimized HCP-loaded ethosomes represent a promising ingredient formulation platform enabling bioactive preservation, formulation stability, and controlled topical performance for collagen-based skin rejuvenation applications.

Dynamic combinatorial chemistry (DCC) is an attractive method to efficiently generate libraries of molecules from simpler building blocks by reversible reactions under thermodynamic control. Here we focus on the chemical modification of DNA oligonucleotides with acyclic diol linkers and demonstrate their potential for the deoxyribonucleic acid functionalization and generation of libraries of reversibly interconverting building blocks. The syntheses of phosphoramidite building blocks derived from D-threoninol are presented in two variants with protected amino or thiol groups. The threoninol building blocks were successfully incorporated via automated solid-phase synthesis into 13mer oligonucleotides. The amino group containing phosphoramidite was used together with complementary single-strand DNA templates that influenced the Watson–Crick base-pairing equilibrium in the mixture with a set of aldehyde modified nucleobases. A significant fraction of all possible base-pair mismatches was obtained, whereas, the highest selectivity (over 80%) was found for the guanine aldehyde templated by the complementary cytosine containing DNA. The elevated occurrence of mismatches can be explained by increased backbone plasticity derived from the linear threoninol building block as a cyclic deoxyribose analogue.