Dynamic Modulation of Enzyme Activity by Near‐Infrared Light

Engineering near‐infrared (NIR) light‐sensitive enzymes remains a huge challenge. A photothermal effect‐associated method is developed for tailoring the enzymatic activity of enzymes by exposure to NIR light. An ultrasmall platinum nanoparticle was anchored in an enzyme to generate local heating upon NIR irradiation, which enhanced the enzyme activity without increasing bulk temperature. Following NIR irradiation, the enzyme activity was tailored rapidly and reversibly, and was modulated by varying laser power density and irradiation time. Four enzymes were engineered, including glucoamylase, glucose oxidase, catalase, and proteinase K with NIR‐light sensitivity, and demonstrated their utility in practical applications such as photolithography and NIR light‐responsive antibacterial or anticancer actions. Our investigation suggests that this approach could be broadly used to engineer enzymes with NIR‐light sensitivity for many biological applications.     

Broadband Light Harvesting and Unidirectional Electron Flow for Efficient Electron Accumulation for Hydrogen Generation

The efficiency of solar hydrogen evolution closely depends on the multiple electrons accumulation on the catalytic center for two‐electron‐involved water reduction. Herein, we report an effective approach to enable broadband light absorption and unidirectional electron flow for efficiently accumulating electrons at active sites for hydrogen evolution by rationally engineering the nanostructure of Pt nanoparticles (NPs), TiO₂, and SiO₂ support. In addition to Schottky‐junction‐driven electron transfer from TiO₂ to Pt, Pt NPs also produce hot electrons by recycling the scattered visible and near‐infrared (vis‐NIR) light of the support. Unidirectional electron flow to active sites is realized by tuning the components spatial distribution. These features collectively accumulate multiple electrons at catalytic Pt sites, thereby affording enhanced activity toward hydrogen evolution under simulated sunlight.     

Quantitation of Femtomolar‐Level Protein Biomarkers Using a Simple Microbubbling Digital Assay and Bright‐Field Smartphone Imaging

Quantitating ultra‐low concentrations of protein biomarkers is critical for early disease diagnosis and treatment. However, most current point‐of‐care (POC) assays are limited in sensitivity. Herein, we introduce an ultra‐sensitive and facile microbubbling assay for the quantification of protein biomarkers with a digital‐readout method that requires only a smartphone camera. We used machine learning to develop a smartphone application for automated image analysis to facilitate accurate and robust counting. Using this method, post‐prostatectomy surveillance of prostate specific antigen (PSA) can be achieved with a detection limit (LOD) of 2.1 fm (0.060 pg mL^?1), and early pregnancy detection using βhCG can be achieved with a of 0.034 mIU mL^?1 (2.84 pg mL^?1). This work provides the proof‐of‐principle of the microbubbling assay with a digital readout as an ultra‐sensitive technology with minimal requirement for power and accessories, facilitating future POC applications.     

Peptide‐Coated Platinum Nanoparticles with Selective Toxicity against Liver Cancer Cells

Peptide‐stabilized platinum nanoparticles (PtNPs) were developed that have significantly greater toxicity against hepatic cancer cells (HepG2) than against other cancer cells and non‐cancerous liver cells. The peptide H‐Lys‐Pro‐Gly‐d Lys‐NH₂ was identified by a combinatorial screening and further optimized to enable the formation of water‐soluble, monodisperse PtNPs with average diameters of 2.5 nm that are stable for years. In comparison to cisplatin, the peptide‐coated PtNPs are not only more toxic against hepatic cancer cells but have a significantly higher tumor cell selectivity. Cell viability and uptake studies revealed that high cellular uptake and an oxidative environment are key for the selective cytotoxicity of the peptide‐coated PtNPs.