Metallo-oxide (MO)-based bioinorganic nanocomposites promise unique structures, physicochemical properties, and novel biochemical functionalities, and within the past decade, investment in research on materials such as ZnO, TiO 2 , SiO 2 , and GeO 2 has significantly increased. Besides traditional approaches, the synthesis, shaping, structural patterning, and postprocessing chemical functionalization of the materials surface is inspired by strategies which mimic processes in nature. Would such materials deliver new technologies? Answering this question requires the merging of historical knowledge and current research from different fields of science. Practically, we need an effective defragmentation of the research area. From our perspective, the superficial accounting of material properties, chemistry of the surfaces, and the behavior of biomolecules next to such surfaces is a problem. This is particularly of concern when we wish to bridge between technologies in vitro and biotechnologies in vivo. Further, besides the potential practical technological efficiency and advantages such materials might exhibit, we have to consider the wider long-term implications of material stability and toxicity. In this contribution, we present a critical review of recent advances in the chemistry and engineering of MO-based biocomposites, highlighting the role of interactions at the interface and the techniques by which these can be studied. At the end of the article, we outline the challenges which hamper progress in research and extrapolate to developing and promising directions including additive manufacturing and synthetic biology that could benefit from molecular level understanding of interactions occurring between inanimate (abiotic) and living (biotic) materials.

The controlled synthesis of ZnO at the micro- and nanoscale has been the focus of significant research due to its importance in electrical and optoelectronic applications, and the potential of tuning its properties at the crystal formation stage. We present a detailed study of ZnO growth processes which supports and consolidates previous findings and gives a clearer understanding of the mechanism of ZnO formation. The influence of synthesis conditions on ZnO formation was investigated by comparison of two different growth routes (Zn­(CH3COO)2–NH3 and Zn­(NO3)2·6H2O−HMTA) both known to result in the formation of wurtzite structured, twinned hexagonal rods of ZnO. The identities of the solid phases formed and supernatants were confirmed by data from SEM, XRD, FTIR, XPS, TGA, and ICP-OES analysis; giving insight into the involvement of multistep pathways. In both cases, reaction takes place via intermediates known as layered basic zinc salts (LBZs) which only later transform to the oxide phase. In the ZnAc2–NH3 system, crystal growth evolves as Zn­(CH3COO)2 → LBZA (A: acetate) → ZnO through a dissolution/reprecipitation process, with the formation of an additional product identified as LBZAC (C: carbonate). In contrast, in the Zn­(NO3)2·6H2O−HMTA system, solid-phase transformation occurs as Zn­(NO3)2·6H2O → LBZN (N: nitrate) → ZnO with no evidence of dissolution. Similar comprehensive studies can be applied to other solid-state processes to further advance functional materials design.

Material binding peptides are proving to have great potential in improving material synthesis and advancing device fabrication; however, their specificity and interaction mechanisms with target surfaces remain largely elusive. This study contributes to the developing understanding of fundamental principles through which ZnO binding peptides (ZnO-BPs) interact with and modify ZnO growth/morphology. The ZnO-BPs used were the reported phage display (PD) identified sequence (G-12 (GLHVMHKVAPPR) and its derivative, GT-16 (GLHVMHKVAPPR-GGGC)) as well as novel sequences generated from postselection modifications including alanine mutants of G-12 (G-12A6, G-12A11, and G-12A12) chosen on the basis of peptide stability calculated in silico. ZnO growth was monitored in the absence and presence of ZnO-BPs during solution synthesis using two different growth routes: the Zn­(NO3)2·6H2O–HMTA system and the Zn­(CH3COO)2–NH3 system. The outcomes of the ZnO synthesis studies demonstrate that a single ZnO-BP can utilize different sequence and concentration dependent mechanisms to control ZnO growth and generate different morphologies. The specific synthesis system used dictated the species present in solution and the solid phases formed, some of which ZnO-BPs could interact with and consequently modify ZnO growth and resultant morphologies. The role of histidine within ZnO-BPs in interaction with ZnO and stabilization of LBZs is also demonstrated.