Fluorescence spectrophotometry for COVID-19 determination in clinical swab samples.

Considering the limitations of the assays currently available for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its emerging variants, a simple and rapid method using fluorescence spectrophotometry was developed to detect coronavirus disease 2019 (COVID-19). Forty clinical swab samples were collected from the nasopharyngeal and oropharyngeal cavities of COVID-19-positive and -negative. Each sample was divided into two parts. The first part of the samples was analyzed using reverse transcription-polymerase chain reaction (RT-qPCR) as the control method to identify COVID-19-positive and -negative samples. The second part of the samples was analyzed using fluorescence spectrophotometry. Fluorescence measurements were performed at excitation and emission wavelengths ranging from 200 to 800 nm. Twenty COVID-19-positive samples and twenty COVID-19-negative samples were detected based on RT-qPCR results. The fluorescence spectrum data indicated that the COVID-19-positive and -negative samples had significantly different characteristics. All positive samples could be distinguished from negative samples by fluorescence spectrophotometry. Principal component analysis showed that COVID-19-positive samples were clustered separately from COVID-19-negative samples. The specificity and accuracy of this experiment reached 100%. Limit of detection (LOD) obtained 42.20 copies/ml (Ct value of 33.65 cycles) for E gene and 63.60 copies/ml (Ct value of 31.36 cycles) for ORF1ab gene. This identification process only required 4 min. Thus, this technique offers an efficient and accurate method to identify an individual with active SARS-CoV-2 infection and can be easily adapted for the early investigation of COVID-19, in general.

Deteksi kapsul gelatin imunitas anti COVID-19 dengan sensor quartz crystal microbalance (QCM) yang jual di pasar X kota Surabaya

Tujuan penelitian ini adalah untuk mengetahui kandungan porcine (babi) atau bovine (sapi) pada kapsul gelatin imunitas anti COVID-19 yang dijual di Pasar X Surabaya Utara. Metode yang digunakan untuk membedakan gelatin babi dan gelatin sapi adalah dengan alat Quartz crystal microbalance (QCM). Pada penelitian ini pendeteksian kapsul gelatin imunitas anti COVID-19 dilakukan dengan alat QCM. Metode penelitian ini dilakukan secara true eksperimental dan pengambilan sampel dengan teknik quota sebesar 3 gram pada masing-masing sampel dengan merk yang berbeda. Hasil penelitian yang dilakukan pada 4 sampel dengan merk berbeda yang berasal dari pasar X daerah Surabaya Utara menunjukkan hasil pendeteksian sebanyak 2 sampel dengan hasil negatif (-) dan 2 sampel dengan hasil positif (-) artinya sampel negatif mengandung gelatin sapi (bovine) dan sampel positif mengandung babi (porcine). Pada sampel kapsul gelatin imunitas yang mengandung gelatin sapi ditandai dengan penurunan frekuensi sedangkan sampel kapsul gelatin imunitas yang mengandung gelatin babi ditandai dengan kenaikan frekuensi.