Fabrication of a Low Cost Superhydrophobic Substrate for Surface Enhanced Laser-Induced Breakdown Spectroscopy and Its Utility through Identification of Electrolyte Variation for Oral Cancer Detection

Ultratrace elemental detections from a limited volume of samples can offer significant benefits in biomedical fields. However, it can be challenging to concentrate the particles being analyzed in a small area to improve the accuracy of detection. Ring-like deposits on the edges of colloidal droplets are a vexing problem in many applications. Herein, we report ultratrace elemental detection using a superhydrophobic surface-enhanced laser-induced breakdown spectroscopy (SELIBS) substrate fabricated by laser ablation followed by a soft lithography technique. In this work, the SELIBS spectra on a superhydrophobic polydimethylsiloxane (PDMS) substrate replicated from a laser-patterned master Teflon substrate are investigated. This work highlights the application of this newly created superhydrophobic substrate for detecting trace elements in body fluids using SELIBS. The developed PDMS substrate was successfully adopted to investigate the electrolyte variation in serum samples of oral cancer patients and normal volunteers. Principal component analysis (PCA) and match-no-match analysis were used to distinguish the elemental variation in cancer and control groups.

Elemental Composition of Betel Leaves Using a Novel Optical Spectroscopic Technique

Objective: Assess trace elements in betel leaves and slaked lime from different regions of Karnataka, India using Laser Induced Breakdown Spectroscopy (LIBS). Materials and Method: Betel leaves from six different regions of Karnataka were obtained and named (for the purpose of the study) BL1, BL2, BL3, BL4, BL5, and BL6 and they were sun-dried. A single tube of slaked lime was obtained from the local ‘paan’ shop. Each dried leaf and a single blob of slaked lime was subjected to elemental analysis using Laser-induced breakdown spectroscopy. Results: A ten-trial experiment was carried out in all six leaves and a blob of the slaked lime. The National Institute of Standards and Technology (NIST) database was used to assess the emission lines. The elements that were predominantly present in all six betel leaves from different regions of Karnataka are calcium, copper, and iron. Slaked lime showed only the presence of calcium. Conclusion: It is widely accepted that the consumption of betel quid causes various changes in the oral mucosa including oral potentially malignant disorders (OPMDs) and oral cancer. It is important to analyze each component of betel quid to understand the disease progression. Copper is found to be relatively higher in betel leaves, and it is known that copper-induced fibrogenesis via the lysyl oxidase pathway in oral submucous fibrosis.

Versatile application of BiVO4/TiO2 S-scheme photocatalyst: Photocatalytic CO2 and Cr(VI) reduction

Herein, the synthesis, characterization, and reduction properties of 2D TiO₂ aerogel powder decorated with BiVO₄ (TiO₂/BiVO₄) were investigated for versatile applications. First, 2D TiO₂ was prepared via lyophilization and subsequently modified with BiVO₄ using a wet impregnation method. The morphology, structure, composition, and optical properties were evaluated using transmission electron microscopy (TEM), X-ray diffractometry (XRD), laser-induced breakdown spectroscopy (LIBS), and diffuse reflectance spectroscopy (DRS), respectively. Significantly enhanced photocurrent densities (by 3-15 times) were obtained for TiO₂/BiVO₄ compared to those of pure TiO₂ and BiVO₄. The reduction of toxic Cr(VI) to Cr(III) was assessed, including the effect of pH on overall photocatalytic efficiency. Under acidic conditions (pH ∼ 2), Cr(VI) reduction efficiency reached 100% within 2 h. For photocatalytic CO₂ reduction, the highest yields of CH₄ and CO were obtained using TiO₂/BiVO₄. A higher efficiency for both applications was achieved because of the better separation of the electron-hole pairs in TiO₂/BiVO₄. The excellent stability of TiO₂/BiVO₄ over repeated runs highlights its potential for use in versatile environmental applications. The efficiency of TiO₂/BiVO₄ is due to the interplay of the structure, morphology, composition, and photoelectrochemical properties that favour the material for the presented herein photocatalytic applications.

LASER as a tool for surface modification of dental biomaterials: A review

In recent years, the application of lasers for modifying the surface topography of dental biomaterials has received increased attention. This review paper aims to provide an overview of the current status on the utilization of lasers as a potential tool for surface modification of dental biomaterials such as implants, ceramics, and other materials used for restorative purposes. A literature search was done for articles related to the use of lasers for surface modification of dental biomaterials in English language published between October 2000 and March 2023 in Scopus, Pubmed and web of science, and relevant articles were reviewed. Lasers have been mainly used for surface modification of implant materials (71%), especially titanium and its alloys, to promote osseointegration. In recent years, laser texturing has also emerged as a promising technique to reduce bacterial adhesion on titanium implant surfaces. Currently, lasers are being widely used for surface modifications to improve osseointegration and reduce peri-implant inflammation of ceramic implants and to enhance the retention of ceramic restorations to the tooth. The studies considered in this review seem to suggest laser texturing to be more proficient than the conventional methods of surface modification. Lasers can alter the surface characteristics of dental biomaterials by creating innovative surface patterns without significantly affecting their bulk properties. With advances in laser technology and availability of newer wavelengths and modes, laser as a tool for surface modification of dental biomaterials is a promising field, with excellent potential for future research.

Post-COVID syndrome screening through breath analysis using electronic nose technology

There is an urgent need to have reliable technologies to diagnose post-coronavirus disease syndrome (PCS), as the number of people affected by COVID-19 and related complications is increasing worldwide. Considering the amount of risks associated with the two chronic lung diseases, asthma and chronic obstructive pulmonary disease (COPD), there is an immediate requirement for a screening method for PCS, which also produce symptoms similar to these conditions, especially since very often, many COVID-19 cases remain undetected because a good share of such patients is asymptomatic. Breath analysis techniques are getting attention since they are highly non-invasive methods for disease diagnosis, can be implemented easily for point-of-care applications even in primary health care centres. Electronic (E-) nose technology is coming up with better reliability, ease of operation, and affordability to all, and it can generate signatures of volatile organic compounds (VOCs) in exhaled breath as markers of diseases. The present report is an outcome of a pilot study using an E-nose device on breath samples of cohorts of PCS, asthma, and normal (control) subjects. Match/no-match and k-NN analysis tests have been carried out to confirm the diagnosis of PCS. The prediction model has given 100% sensitivity and specificity. Receiver operating characteristics (ROC) has been plotted for the prediction model, and the area under the curve (AUC) is obtained as 1. The E-nose technique is found to be working well for PCS diagnosis. Our study suggests that the breath analysis using E-nose can be used as a point-of-care diagnosis of PCS.

Trial registration

Breath samples were collected from the Kasturba Hospital, Manipal. Ethical clearance was obtained from the Institutional Ethics Committee, Kasturba Medical College, Manipal (IEC 60/2021, 13/01/2021) and Indian Council of Medical Research (ICMR) (CTRI/2021/02/031357, 06/02/2021) Government of India; trials were prospectively registered.