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Nanodiamonds (NDs) have unique optical and mechanical characteristics, surface chemistry, extensive surface area and biocompatibility, and they are nontoxic, rendering them suitable for a diverse range of applications. Recently, NDs have received significant attention in nano-biomedical engineering. This review discusses the recent advancement of NDs’ biomedical engineering, historical background, basic introduction to nanoparticles and development. We summarize NDs’ synthesis technique, properties and applications. Two methodologies are used in ND synthesis: bottom-up and top-down. We cover synthesis methods, including detonation, ball milling, laser ablation, chemical vapor deposition (CVD) and high pressure and high temperature (HPHT); discuss the properties of NDs, such as fluorescence and biocompatibility. Due to these properties, NDs have potential applications in biomedical engineering, including bioimaging, biosensing, drug delivery, tissue engineering and protein mimics. Further, it provides an outlook for future progress, development and application of NDs in biological and biomedical areas.

In this study, the coupling and the relative sensitivity characteristics of a Dual-Core photonic crystal fiber (DC-PCF)-based liquid sensor are evaluated by employing the full-vectorial finite element method (FV-FEM). The simulation results demonstrate that coupling length of the proposed sensor varies between 2mm and 0.2mm length at wide wavelength range (800–1600nm) for low index analytes (1.33–1.36). Besides, birefringence of order $\approx 10^{-4}$ is reported. It is found that analyte with 1.36 index reaches higher sensitivity levels. On the other hand, the coupling length of the proposed sensor can be optimized with the ellipticity ratio of the central core hole. Bending analysis on coupling length and optical power fluctuations is also reported. It is found that the power flow in one core is increasing almost 90% towards the bending direction. The proposed structure with simple design parameters has a great potential in various biomedical applications including DNA detection and can also be employed as fiber-based refractometer in various sensing applications.

Noble metal nanoparticles exhibit strong surface plasmon resonance (SPR) and have been utilized in many chemical, biological and electronic applications. Recent advances on metal-enhanced optical properties demonstrated that the quantum yield and photo-stability of the fluorophores can be significantly enhanced when they are in the proximity of the metal surface, that will benefit many fluorescence-based applications. In this review article we first discuss the fundamental concepts of metal-enhanced optical properties and the recent achievements of metal-enhanced fluorescence of organic fluorophores and quantum dots, as well as metal-enhanced phosphorescence of organic molecules and upconversion nanoparticles that have long life times. Finally, we present recent applications of metal-enhanced optical properties in biosensing and bioassays, photodynamic therapy and optoelectronics.

I was fortunate to work with/for Dr Britton Chance as his postdoctoral fellow, in the Biochemistry and Biophysics Department at the University of Pennsylvania, between August 1991 and January 1994. As anyone who worked for him, I had a sufficient dosage of "Britton Chance" over the years. Initially, to me, I felt that he was someone who was above regular people and far away to reach. Then I became to know him as a person, who was simple and complicated at the same time, with a persistent pursuit for his life interests, i.e., the advancement in science related to human health. As far as it goes to science (and perhaps with sailing), he had few boundary: He communicated with any age group, any one from any country with any cultural background. Any scientists were welcomed to his lab, his own house, and even his boat. He was happy with minimal material things. He kept his friendship faithfully. From him, I came to know how much one person can actually do during a life time. I am very grateful that I got to know him during my life path. In this paper, I list some of my experiences with him scientifically and also how and what I learned from him impacted my research and personal life.

Single- or few-layer black phosphorus (FLBP) has attracted great attentions in scientific community with its excellent properties, including biodegradability, unique puckered lattice configuration, attractive electrical properties and direct and tunable band gap. In recent years, FLBP has been widely studied in bio-photonic fields such as photothermal and photodynamic therapy, drug delivery, bioimaging and biosensor, showing attractive clinical potential. Because of the marked advantages of FLBP nanomaterials in bio-photonic fields, this review article reviews the latest advances of biomaterials based on FLBP in biomedical applications, ranging from biocompatibility, medical diagnosis to treatment.

Black phosphorus (BP) or phosphorene, a new superstar among two-dimensional (2D) materials, has sparked huge scientific interest since its discovery in 2014. BP offers unique characteristics including high drug loading efficiency, excellent photodynamic and photothermal properties and good biocompatibility. These characteristics expand versatility of BP in nanomedicine. Although the outlook of BP seems promising, its practical biomedical applications are still at the very initial stage especially in comparison to other thoroughly investigated inorganic nanomaterials. This paper reviews BP structure and properties as well as its preparation approaches with the emphasis on techniques to improve BP stability and biocompatibility for their further usage in physiological environment. Meanwhile, recent progress made in various biomedical research fields from bioimaging to biosensing is discussed. Last, but not least, current challenges and prospects for BP in biomedicine are briefly examined, which will be useful to guide future developments of BP.

Synthetic nanoporous membranes have been used in numerous biosensing applications, such as glucose detection, nucleic acid detection, bacteria detection, and cell-based sensing. The increased surface affinity area and enhanced output sensing signals make the nanoporous membranes increasingly attractive as biosensing platforms. Surface modification techniques can be used to improve surface properties for realizable bioanalyte immobilization, conjugation, and detection. Combined with realizable detection techniques such as electrochemical and optical detection methods, nanoporous membrane–based biosensors have advantages, including rapid response, high sensitivity, and low cost. In this paper, an overview of nanoporous membranes for biosensing application is given. Types of nanoporous membranes including polymer membranes, inorganic membranes, membranes with nanopores fabricated using nanolithography, and nanotube-based membranes are introduced. The fabrication techniques of nanoporous membranes are also discussed. The key requirements of nanoporous membranes for biosensing applications include surface functionality for bioanalyte immobilization, biocompatibility, mechanical and chemical stability, and anti-biofouling capability. The recent advances and development of nanoporous membrane–based biosensors are discussed, especially for the sensing mechanism and surface functionalization strategies. Finally, the challenges and future development of nanoporous membrane for biosensing applications are discussed.

Gap tunable gold nanoslit arrays were fabricated by interference lithography and investigated numerically to understand the impact of fabrication errors on plasmonic responses. To fabricate the gap tunable gold nanoslit arrays, photoresist nanoslit arrays on quartz substrate were first formed by laser interference, and then converted to gold nanoslit array on glass substrate by perpendicular gold deposition and photoresist lift-off. Because the photoresist nanoslit has a sinusoidal profile due to the laser light interference lithography, different photoresist development time from 20s to 30s can tune the photoresist width from 100nm to 70nm, thus allows the gap-width-tuned metallic nanoslits to be attained accordingly. The optical properties of the fabricated gold nanoslit arrays were investigated experimentally and theoretically by studying the absorption in the transmission spectra. Within the wavelength range of 400nm to 860nm, the nanoslit in air has two prominent absorption peaks at 500nm and 670nm. It is found that a simulation model with gold nanoslit fabrication errors such as size variation, chromium adhesive layer and gold residue in nanoslit gaps considered can better match the simulation peaks with the experiments. The simulation of the gold nanoslit array in air indicates that the 500nm peak includes the interband transition and surface plasmon polariton (SPP) at air-gold surface, and the other peak at 670nm is SPP at glass side. The two SPP peaks are both sensitive to the refractive index of surrounding solution, with sensitivities of the two peaks demonstrated to be 267nm/RIU and 111nm/RIU in experiments, and 462nm/RIU and 180nm/RIU by simulation. The lower sensitivity detected by experiments might be due to some air bubbles in the flow cell reducing the effective refractive index around the nanoslit. The shorter wavelength SPP mode is 2.4 (in experiments) or 2.6 times (by simulation) more sensitive than the long wavelength SPP mode because its plasmonic field concentrates on water-gold surface. The plasmonic responses we simulated with fabrication errors explained our experimental investigations, and deepened our understanding on the application of the gold nanoslit array for refractive index-based biosensing.