# Biosynthesis of Silver Nanoparticles Using _Tabernaemontana ventricosa_ Extracts
## 1 Introduction  
The contemporary trends in nanoscience have prompted the frequent synthesis and applications of silver nanoparticles (AgNPs) [1, 2, 3]. Nanoparticles (NPs) are often described as extremely tiny materials that exhibit nanoscale dimensions ranging from 1 to 100 nm [1, 4, 5, 6]. The specific features of AgNPs such as their large surface-area-to-volume ratio, size, shape, and morphology have optimized their activity in a variety of applications, which include health, medicine, chemistry, food, textiles, agricultural sectors, and nanofluids (energy harvesting and heat transfer enhancing) [6, 7, 8, 9, 10, 11]. Furthermore, recently, silver nanoparticles have been frequently used as antibacterial materials against disease-causing microbes [12]. The production of NPs has been reported using chemical and physical methods; however, current research has revealed that the biological synthesis (i.e., use of living organisms) of AgNPs has driven research toward a \"Green synthesis\" approach [1, 2, 13, 14]. The greenproduction of AgNPsPs is considered simplistic, cost-effective, environmentally friendly, safer, and easily upscaled for large-scale synthesis [15; 16]. Overall, the main goal of green synthesis is to ensure that the safety and reliability of AgNPs are enhanced, therefore reducing the usage of hazardous raw sources [17]. Hybrid methods are categorized into two approaches [18; 19]. Firstly, the \"Bottom-up\" approach involves the synthesis of NPs from elemental entities such as atoms and molecules using chemicals or biological synthesis [8; 18; 19]. This technique often produces colloidal dispersions of homogenous particles with fewer defects [20]. Secondly, the \"Top-down\" approach is a process whereby NPs are reduced in size until it reaches a suitable material [8; 18; 19]. This method consists of chemical and physical techniques that are often energy-consuming and produce imperfect NPs [18; 19; 21]. According to [PERSON] [22], biosynthetic synthesis using a greener approach is often preferred over conventional techniques since it is relatively simple, requires less time and energy, and does not involve the use of toxic chemicals.  
The green synthesis of NPs utilizing whole plants, or their respective extracts, has received more attention than the many biological techniques since plants are often free of harmful chemicals and contain natural capping agents, which provide a greener platform to produce nanoparticles [17; 23]. As such, there have been several reports of AgNPs synthesized using medicinal plant extracts such as _Ceratonia silique_[24], _Ocimum sanctum_[25], _Coleus aromaticus_[26], _Jatropha curcas_[27], _Litchi chtinensis_[28], and _Tabernaemontana divariatica_[2; 29]. The current study investigated the use of _Tabernaemontana ventricosa_, a medium-sized latex-bearing plant belonging to Apocynaceae for the synthesis of AgNPs [30]. This species is randomly distributed in Nigeria, Ghana, Kenya, and South Africa [31]. All parts of _T. ventricosa_ are often used in traditional medicine to treat fever, wounds, and sore eyes [32]. The leaves and latex are rich in alkaloids and have been reported to contain antiamoebic activity [31].  
A considerable amount of AgNPs has been synthesized using several medicinal plant species within the genus _Tabernaemontana_; however, there remains a lack of research concerning _T. ventricosa_ extracts. Hence, the current study aimed to biologically synthesize AgNPs using various leaf and stem extracts (methanolic, fresh, and powdered) of _T. ventricosa_. Additionally, the study aimed to determine whether the differences in organ type influenced the morphology (particle size and shape) and chemical nature of the synthesized AgNPs. The synthesis and characterization of the AgNPs from _T. ventricosa_ extracts were evaluated for the first time in this study.