Bioassay engineering: a combined label-free and fluorescence approach to optimize HER2 detection in complex biological media.

We report on the combined label-free/fluorescence use of one-dimensional photonic crystals to optimize cancer biomarker detection in complex biological media. The optimization of the assay working parameters permits us to maximize the final response of the biosensor. The detection approach utilizes a sandwich assay, in which one-dimensional photonic crystals sustaining Bloch surface waves are modified with monoclonal antibodies in order to guarantee high specificity during biological recognition. The multiple outcomes generated by such optimization experiments permitted us to determine the effective capture efficiency and the repeatability of the immobilization process, which was estimated to be close to 5%. By exploiting the resolution of the fluorescence operation mode, we studied non-specific interactions in different blocking agents, different analyte diluting buffers, and diverse concentrations of the detection antibody. As a clinically relevant biomarker, we selected the trans-membrane receptor tyrosine kinase HER2. HER2 regulates a variety of cell proliferation, growth, and differentiation pathways and its over-expression occurs in approximately 20-30% of breast cancer worldwide. As a final application, we transferred all the optimized working parameters to HER2 cancer biomarker assays in a complex biological environment. The label-free and fluorescence results obtained by analyzing MCF-7 (HER2 low positive) and 32D (HER2 negative) cell lysates demonstrate that we can successfully discriminate the two lysates.

Emerging Approaches to DNA Data Storage: Challenges and Prospects.

With the total amount of worldwide data skyrocketing, the global data storage demand is predicted to grow to 1.75 × 1014 GB by 2025. Traditional storage methods have difficulties keeping pace given that current storage media have a maximum density of 103 GB/mm3. As such, data production will far exceed the capacity of currently available storage methods. The costs of maintaining and transferring data, as well as the limited lifespans and significant data losses associated with current technologies also demand advanced solutions for information storage. Nature offers a powerful alternative through the storage of information that defines living organisms in unique orders of four bases (A, T, C, G) located in molecules called deoxyribonucleic acid (DNA). DNA molecules as information carriers have many advantages over traditional storage media. Their high storage density, potentially low maintenance cost, ease of synthesis, and chemical modification make them an ideal alternative for information storage. To this end, rapid progress has been made over the past decade by exploiting user-defined DNA materials to encode information. In this review, we discuss the most recent advances of DNA-based data storage with a major focus on the challenges that remain in this promising field, including the current intrinsic low speed in data writing and reading and the high cost per byte stored. Alternatively, data storage relying on DNA nanostructures (as opposed to DNA sequence) as well as on other combinations of nanomaterials and biomolecules are proposed with promising technological and economic advantages. In summarizing the advances that have been made and underlining the challenges that remain, we provide a roadmap for the ongoing research in this rapidly growing field, which will enable the development of technological solutions to the global demand for superior storage methodologies.