## 1 Introduction  
Application of papers in analytical platforms was known as early as the 17 th century with the use of cellulose fibrous structure for chromatography [1]. Recent advances in specific healthcare areas such as visual bio-diagnostics and hand-held detection devices have opened a new demand for the application of fiber-based materials [2; 3; 4]. Various paper-based bio-analytical platforms were developed in the last decades such as dot-immunoglobin assays (DIAs), microfluidic paper-based analytical devices (\(\upmu\)PADs), laminated paper-based analytical devices (LPADs), immunospot, nitrocellulose pads (NC-PADs) and paper-based ELISA (enzyme-linked immunosorbent assay) (P-ELISA) well plates [2]. Fabrication of these platforms mainly involves techniques such as printing, waxing, patterning and heating [2]. Those techniques are promising as potential healthcare solutions, yet for addressing point-of-care issues, better control over the paper source itself is imperative [5]. Although application of papers has made an obvious shift in the healthcare paradigm and opened a wide outlook into the bio-analytical domain, developed paper-based platforms are still suffering from a lack of reproducibility and limited detection options [2; 6]. In particular, paper-based analytical devices suffer from one inherent limitation common in majority of these platforms: insufficient level of sensitivity and accuracy [2; 7]. Fiber segments integrated in existing paper platforms are commercially available nitrocellulose (NC) with hydroxyl groups (-OH) as a part of the chemical structure. Different modification techniques such as oxidation, etherification, esterification, etc. have been used to convert the fairly unreactive -OH functional groups to more reactive surface carboxyl (-COOH) groups [8; 9; 10; 11]. Apart from the intricacy of such modification techniques, they often compromise the NC characteristics during the modification procedure. Most importantly, the properties of NC materials such as porosity and permeability vary from one manufacturer to another and it is difficult to maintain consistency over those parameters when dealing with commercial paper products. In order to overcome those limitations there is necessity of developing a customized material with a higher degree of control over improved material characteristics. In a novel approach presented in this paper, we have developed a polymer-coated fiber mat that can be a suitable substitution for the papers in the existing paper-based analytical devices (Figure 1). Furthermore, we fabricated a new class of fiber (or paper)-assisted analytical well plate that, while being simple and cost effective, addresses some of the major drawbacks of the previously developed fiber-based platforms. The proposed strategy introduces fiber mats into the assay by incorporating them into the lid of the well plate using pillar extensions, as presented in Figure 2. This new design allows the fiber mats to physically penetrate the assay. For that reason, the developed platform is named intrant ELISA (abbreviated as i-ELISA; the word \"intrant\" is taken from the Latin root for the \"entering object\"). In this new strategy, protein immobilization and subsequent detection of the target analyte takes place on both sides of the platform (inside the well and on the fiber mat). This arrangement enhances the chance for bio-recognition as the specific surface area is significantly increased, which in turn enables early detection of diseases such as dengue virus. Prevalent in tropical and subtropical areas, dengue fever (DF) is considered as one of the deadliest diseases that can be a universal threat by individuals who contract the infection while traveling abroad [12; 13; 14]. Dengue starts with simple dengue fever (DF) but can foster severe manifestations such as dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) [12; 14; 15; 16; 17]. With a yearly 400 million infection cases and 21,000 fatalities, effective early dengue detection remains a major challenge.