Dr. RAMASWAMY SANDEEP PERALA

In this work, we report a polyol route for easy synthesis of upconversion (UC) phosphor nanoparticles, YVO₄:Ho³⁺-Yb³⁺-K⁺, which enables large-scale production and enhancement of luminescence. Upon 980 nm laser excitation, the UC emission spectrum shows a sharp bright peak at ∼650 nm of Ho³⁺ ion; and the luminescence intensity increases twofold upon K⁺ codoping. Upon 300 nm excitation, the downconversion emission spectrum shows a broad peak in the 400–500 nm range (related to the charge transfer band of V–O) along with Ho³⁺ peaks. In addition, the polyethylene glycol-coated UC nanoparticles are highly water-dispersible and their hybrid with Fe₃O₄ nanoparticles shows magnetic-luminescence properties. A hyperthermia temperature is achieved from this hybrid. Both UC and hybrid nanoparticles show interesting security ink properties upon excitation by a 980 nm laser. The particles are invisible in normal light but visible upon 980 nm excitation and are useful in display devices, advanced anticounterfeiting purposes, and therapy of cancer via hyperthermia and bioimaging (since it shows red emission at ∼650 nm). Using UC nanoparticles, detection of uranyl down to 20 ppm has been achieved.

19 July 2021 in ACS Omega

Journal Article

Brilliant Nonlinear Optical Response of Ho³⁺ and Yb³⁺ Activated YVO₄ Nanophosphor and Its Conjugation with Fe₃O₄ for Smart Anticounterfeit and Hyperthermia Applications

RAMASWAMY SANDEEP PERALA

Rashmi Joshi

Bheeshma Pratap Singh

Venkata Nagendra Kumar Putta

Raghunath Acharya

Raghumani Singh Ningthoujam

YVO₄:Ho³⁺/Yb³⁺ nanophosphors prepared by an effective polyol-mediated route show dual-mode behavior in photoluminescence. Upon 980 nm excitation, the upconversion red emission spectrum exhibits a bright red peak at ∼650 nm, characteristic of the electronic transition of the Ho³⁺ ion via involvement of two-photon absorption, which has been confirmed by the power-dependent luminescence study. Moreover, at 300 nm excitation, downconversion emission peaks are observed at 550, 650, and ∼755 nm. The nonradiative resonant energy transfer occurs from the V–O charge transfer band to Ho³⁺ ions, resulting in an improved emission of Ho³⁺ ions. Moreover, polyethylene glycol-coated nanoparticles make it suitable for water dispersibility; and these particles are conjugated with Fe₃O₄ nanoparticles to form magnetic–luminescent hybrid nanoparticles. Highly water-dispersible magnetic–luminescent hybrid material attained the hyperthermia temperature (∼42 °C) under an applied AC magnetic field. The specific absorption rate value is found to be high (138 W/g), which is more than that of pure superparamagnetic Fe₃O₄ nanoparticles. At 300 nm excitation, the high quantum yield value of ∼27% is obtained from YVO₄:Ho³⁺/Yb³⁺, which suggests that it is a good phosphor material. By employing the neutron activation analysis technique, it is shown that nanophosphor particles can absorb Au³⁺ up to the ppm level. Interestingly, such nanophosphor also shows the potentiality for anticounterfeiting applications.

22 February 2023 in Biosensors

Journal Article

A Brief Review of Graphene-Based Biosensors Developed for Rapid Detection of COVID-19 Biomarkers

Narendhar Chandrasekar

Balaji Ramachandran

RAMASWAMY SANDEEP PERALA

Nik Humaidi Nik Zulkarnine

KIRUBANANDAN SHANMUGAM

Saravanan Govindaraju

The prevalence of mutated species of COVID-19 antigens has provided a strong impetus for identifying a cost-effective, rapid and facile strategy for identifying the viral loads in public places. The ever-changing genetic make-up of SARS-CoV-2 posts a significant challenfge for the research community to identify a robust mechanism to target, bind and confirm the presence of a viral load before it spreads. Synthetic DNA constructs are a novel strategy to design complementary DNA sequences specific for antigens of interest as in this review’s case SARS-CoV-2 antigens. Small molecules, complementary DNA and protein–DNA complexes have been known to target analytes in minimal concentrations. This phenomenon can be exploited by nanomaterials which have unique electronic properties such as ballistic conduction. Graphene is one such candidate for designing a device with a very low LOD in the order of zeptomolar and attomolar concentrations. Surface modification will be the significant aspect of the device which needs to have a high degree of sensitivity at the same time as providing a rapid signaling mechanism.

1 January 2019 in Journal of Radiation and Cancer Research

Journal Article

Heat generation from magnetic fluids under alternating current magnetic field or induction coil for hyperthermia-based cancer therapy: Basic principle

Raghumani Singh Ningthoujam

Rashmi Joshi

RAMASWAMY SANDEEP PERALA

Manas Srivastava

Bheeshma Pratap Singh

Superparamagnetic particles (SUPs) have been used in many applications in the area of hyperthermia-based cancer treatment, as a magnetic resonance imaging contrast agent, as a carrier for drug, in the removal of toxic ions, etc. When SUPs are dispersed in liquid, they can experience Brownian motion and Néel's spin relaxations. In the presence of direct current magnetic field, SUPs do not show a hysteresis loop. Because of this, they are unable to produce heat. However, in alternating current magnetic field (AMF) of a few kHz and small magnetic fields, they can generate heat. For the treatment of cancer, hyperthermia temperature of 43°C is required, at which temperature cancer cells can be killed selectively, but normal cells can survive. The theory behind heat generation from SUPs in the presence of AMF will be discussed in this work.

About Me

Dr. Ramaswamy Sandeep Perala is currently an Assistant Professor in the Department of Chemistry at Gachon University, South Korea. He is dedicated to the development of advanced nanomaterials and graphene-based technologies aimed at practical applications. His research integrates materials chemistry, nanotechnology and biosensing to various innovative solutions for healthcare, environmental monitoring, energy storage and smart sensing applications. He earned his Ph.D in Chemistry from GITAM University in collaboration with BARC, Mumbai, India. His research work based on lanthanide-doped nanophosphor materials for various applications, including bioimaging, hyperthermia, anti-counterfeiting and environmental remediation. Over the years, Dr. Perala has developed a strong proficiency in the design of functional nanomaterials, graphene based field-effect transistor (FET) biosensors and magnetic-luminescent nanomaterials. His research was published in prestigious international journals such as Coordination Chemistry Reviews, Materials Science and Engineering R, ACS Applied Materials and Interfaces, Device (Cell Press), ACS Applied Optical Materials, Journal of Alloys and Compounds, Industrial and Engineering Chemistry, ACS Omega and etc., showcasing his dedication to enhancing both fundamental science and applied technologies. His ultimate goal is to apply groundbreaking materials research to develop technologies that enhance quality of life and address worldwide challenges.

Dr. RAMASWAMY SANDEEP PERALA

Dr. RAMASWAMY SANDEEP PERALA

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About Me