Taking advantage of the high impermeability property of graphene and the sharp surface plasmon resonance (SPR) curve of silver, we numerically demonstrate that SPR imaging biosensors with a graphene-on-silver substrate can be used to achieve the dramatically high sensitivity as well as to prevent silver oxidation. Results of our numerical study show that a silver substrate with a few graphene layers can significantly increase the imaging sensitivity, compared to the conventional gold-film-based SPR imaging biosensor. In particular, single layered graphene deposited on the 60-nm thick silver film amplifies the SPR imaging signal more than three times. Therefore, the proposed SPR substrate could potentially open a new possibility of SPR imaging detection for sensitive and high-throughput assessment of multiple biomolecular interactions.

Counterfeit medicines are a fundamental security problem. Counterfeiting medication poses a tremendous threat to patient safety, public health, and the economy in developed and less developed countries. Current solutions are often vulnerable due to the limited security levels. We propose that the highest protection against counterfeit medicines would be a combination of a physically unclonable function (PUF) with on-dose authentication. A PUF can provide a digital fingerprint with multiple pairs of input challenges and output responses. On-dose authentication can verify every individual pill without removing the identification tag. Here, we report on-dose PUFs that can be directly attached onto the surface of medicines, be swallowed, and digested. Fluorescent proteins and silk proteins serve as edible photonic biomaterials and the photoluminescent properties provide parametric support of challenge-response pairs. Such edible cryptographic primitives can play an important role in pharmaceutical anti-counterfeiting and other security applications requiring immediate destruction or vanishing features.

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Owing to the low-loss and high refractive index variations derived from the basic building block of bone structure, we, for the first time to our knowledge, demonstrate coherent random lasing action originated from the bone structure infiltrated with laser dye, revealing that bone tissue is an ideal biological material for random lasing. Our numerical simulation shows that random lasers are extremely sensitive to subtle structural changes even at nanoscales and can potentially be an excellent tool for probing nanoscale structural alterations in real time as a novel spectroscopic modality.

Coherent backscattering (CBS) of light in random media has been previously investigated by use of coherent light sources. Here we report a novel method of CBS measurement that combines low spatial coherence, broadband illumination, and spectrally resolved detection. We show that low spatial coherence illumination leads to an anomalously broad CBS peak and a dramatic speckle reduction; the latter is further facilitated by low temporal coherence detection. Thus CBS can be observed in biological tissue and other media that previously were beyond the reach of conventional CBS measurements. We also demonstrate, for the first time to our knowledge, spectroscopic analysis of CBS. CBS spectroscopy may find important applications in probing random media such as biological tissue in which depth-selective measurements are crucial.

Light in biological media is known as freely diffusing because interference is negligible. Here, we show Anderson light localization in quasi-two-dimensional protein nanostructures produced by silkworms (Bombyx mori). For transmission channels in native silk, the light flux is governed by a few localized modes. Relative spatial fluctuations in transmission quantities are proximal to the Anderson regime. The sizes of passive cavities (smaller than a single fibre) and the statistics of modes (decomposed from excitation at the gain–loss equilibrium) differentiate silk from other diffusive structures sharing microscopic morphological similarity. Because the strong reflectivity from Anderson localization is combined with the high emissivity of the biomolecules in infra-red radiation, silk radiates heat more than it absorbs for passive cooling. This collective evidence explains how a silkworm designs a nanoarchitectured optical window of resonant tunnelling in the physically closed structures, while suppressing most of transmission in the visible spectrum and emitting thermal radiation.

There has been a significant interest in developing depth-selective optical interrogation of biological tissue in general and superficial (e.g. mucosal) tissue in particular. We report an in vivo polarization gating fiber-optic probe that obtains backscattering spectroscopic measurements from a range of near-surface depths (100µm -200µm). The design and testing was performed with polarized light Monte Carlo simulations and in tissue model experiments. We used the probe to investigate mucosal changes in early carcinogenesis. Measurements performed in the colonic mucosa of 125 human subjects provide the first in vivo evidence that mucosal blood supply is increased early in carcinogenesis not only in precancerous adenomatous lesions but also in the histologically normalappearing tissue surrounding these lesions. This effect was primarily limited to the mucosal microcirculation and was not present in the larger blood vessels located deeper in colonic tissue.

BackgroundTwo primary objectives when caring for older adults are to slow the decline to a worsened frailty state and to prevent disability. Telemedicine may be one method of improving care in this population. We conducted a secondary analysis of the Tele-ERA study to evaluate the effect of home telemonitoring in reducing the rate of deterioration into a frailty state and death in older adults with comorbid health problems.MethodsThis trial involved 205 adults over the age of 60 years with a high risk of hospitalization and emergency department visits. For 12 months, the intervention group received usual medical care and telemonitoring case management, and the control group received usual care alone. The primary outcome was frailty, which was based on five criteria, ie, weight loss, weakness, exhaustion, low activity, and slow gait speed. Participants were classified as frail if they met three or more criteria; prefrail if they met 1–2 criteria; and not frail if they met no criteria. Both groups were assessed for frailty at baseline, and at 6 and 12 months. Frailty transition analyses were performed using a multiple logistic regression method. Kaplan–Meier and Cox proportional hazards methods were used to evaluate each frailty criteria for mortality and to compute unadjusted hazard ratios associated with being telemonitored, respectively. A retrospective power analysis was computed.ResultsDuring the first 6 months, 19 (25%) telemonitoring participants declined in frailty status or died, compared with 17 (19%) in usual care (odds ratio 1.41, 95% confidence interval [CI] 0.65–3.06, P = 0.38). In the subsequent 6 months, there was no transition to a frailty state, but seven (7%) participants from the telemonitoring and one (1%) from usual care group died (odds ratio 5.94, 95% CI 0.52–68.48, P = 0.15). Gait speed (hazards ratio 3.49, 95% CI 1.42–8.58) and low activity (hazards ratio 3.10, 95% CI 1.25–7.71) were shown to predict mortality.ConclusionThis study did not provide sufficient evidence to show that the telemonitoring group did better than usual care in reducing the decline of frailty states and death. Transitions occurred primarily in the first 6 months.