Microfluidic devices and biochips offer miniaturized laboratories for the separation, reaction, and analysis of biochemical materials with high sensitivity and low reagent consumption. The integration of functional or biomimetic elements further functionalizes microfluidic devices for more complex biological studies. The recently proposed ship-in-a-bottle integration based on laser direct writing allows the construction of microcomponents made of photosensitive polymer inside closed microfluidic structures. Here, we expand this technology to integrate proteinaceous two-dimensional (2D) and three-dimensional (3D) microstructures with the aid of photo-induced cross-linking into glass microchannels. The concept is demonstrated with bovine serum albumin and enhanced green fluorescent protein, each mixed with photoinitiator (Sodium 4-[2-(4-Morpholino) benzoyl-2-dimethylamino] butylbenzenesulfonate). Unlike the polymer integration, fabrication over the entire channel cross-section is challenging. Two proteins are integrated into the same channel to demonstrate multi-protein patterning. Using 50% w/w glycerol solvent instead of 100% water achieves almost the same fabrication resolution for in-channel fabrication as on-surface fabrication due to the improved refractive index matching, enabling the fabrication of 3D microstructures. A glycerol-water solvent also reduces the risk of drying samples. We believe this technology can integrate diverse proteins to contribute to the versatility of microfluidics.

A recent advancement in perovskite solar cells (PSCs) is the emergence of spontaneous heterointerface modulators (SHMs), which eliminate the additional processing required for conventional heterointerface modification. Among SHMs, alkyl‐primary‐ammonium‐bis(trifluoromethylsulfonyl)imides (RA‐TFSIs), used as hole‐transport material (HTM) additives, enable spontaneous perovskite passivation. Upon HTM deposition, RA cations passivate the perovskite surface through strong adsorption via the ammonium (NH ₃ ⁺ ) moiety. However, conventional RA‐TFSIs only passivate A ‐site defects, limiting their effectiveness. Moreover, RA components with multiple functional groups have not been explored. Here, we propose a strategy to suppress multiple defect sites using a spontaneous passivator with dual functional groups. 2‐thiophene‐ethyl‐ammonium‐TFSI (TEA‐TFSI) is newly synthesized and verified as a spontaneous perovskite passivator for n–i–p PSCs employing thermally stable poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine] (PTAA) as the HTM. Spontaneous passivation using TEA‐TFSI forms a monolayer‐like overlayer, where TEA cations are adsorbed at both A ‐ and X ‐site defects via ammonium and thiophene moieties, respectively, overcoming the single‐site limitation of RA‐TFSIs. The TEA overlayer also improves PTAA adhesion. Consequently, PSCs achieve power conversion efficiencies of 22.2% (≈0.12 cm ² minicells) and 21.7% (≈1.6 cm ² minimodules, active area: 1.41 cm ² ), respectively, with thermal stability. This work establishes a general design principle for multifunctional spontaneous passivators and advances materials science.

Femtosecond laser direct write (fs-LDW) is a promising technology for three-dimensional (3D) printing due to its high resolution, flexibility, and versatility. A protein solution can be used as a precursor to fabricate 3D proteinaceous microstructures that retain the protein's native function. The large diversity of protein molecules with different native functions allows diverse applications of this technology. However, our limited understanding of the mechanism of the printing process restricts the design and generation of 3D microstructures for biomedical applications. Therefore, we used eight commercially available homopeptides as precursors for fs-LDW of 3D structures. Our experimental results show that tyrosine, histidine, glutamic acid, and lysine contribute more to the fabrication process than do proline, threonine, phenylalanine, and alanine. In particular, we show that tyrosine is highly beneficial in the fabrication process. The beneficial effect of the charged amino acids glutamic acid and lysine suggests that the printing mechanism involves ions in addition to the previously proposed radical mechanism. Our results further suggest that the uneven electron density over larger amino acid molecules is key in aiding fs-LDW. The findings presented here will help generate more desired 3D proteinaceous microstructures by modifying protein precursors with beneficial amino acids. STATEMENT OF SIGNIFICANCE: Femtosecond laser direct write (fs-LDW) offers a three-dimensional (3D) printing capability for creating well-defined micro-and nanostructures. Applying this technology to proteins enables the manufacture of complex biomimetic 3D micro-and nanoarchitectures with retention of their original protein functions. To our knowledge, homopeptides themselves have never been used as precursor for fs-LDW so far. Our study gains several new insights into the 3D printing mechanism of pure protein for the first time. We believe that the experimental evidence presented greatly benefits the community of 3D printing of protein in particular and the biomaterial science community in general. With the gained insight, we aspire to expand the possibilities of biomaterial and biomedical applications of this technique.